Use the Chunk API consistently

This commit replaces the usage of List with Chunk
where appropriate. Summary of changes:

- The Chunk class was moved from the `org.springframework.batch.core.step.item` package to the `org.springframework.batch.item` package
- The signature of the method `ItemWriter#write(List)` was changed to `ItemWriter#write(Chunk)`
- All implementations of `ItemWriter` were updated to use the Chunk API instead of List
- All methods in the `ItemWriteListener` interface were updated to use the Chunk API instead of List
- All implementations of `ItemWriteListener` were updated to use the Chunk API instead of List
- The constructor of `ChunkRequest` was changed to accept a Chunk instead of a Collection of items
- The return type of `ChunkRequest#getItems()` was changed from List to Chunk

Resolves #3954

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/Chunk.java

@@ -0,0 +1,264 @@
+/*
+ * Copyright 2006-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.batch.item;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * Encapsulation of a list of items to be processed and possibly a list of failed items to
+ * be skipped. To mark an item as skipped clients should iterate over the chunk using the
+ * {@link #iterator()} method, and if there is a failure call
+ * {@link Chunk.ChunkIterator#remove()} on the iterator. The skipped items are then
+ * available through the chunk.
+ *
+ * @author Dave Syer
+ * @author Mahmoud Ben Hassine
+ * @since 2.0
+ */
+public class Chunk<W> implements Iterable<W>, Serializable {
+
+	private List<W> items = new ArrayList<>();
+
+	private List<SkipWrapper<W>> skips = new ArrayList<>();
+
+	private List<Exception> errors = new ArrayList<>();
+
+	private Object userData;
+
+	private boolean end;
+
+	private boolean busy;
+
+	public Chunk(W... items) {
+		this(Arrays.stream(items).toList());
+	}
+
+	public static <W> Chunk<W> of(W... items) {
+		return new Chunk<>(items);
+	}
+
+	public Chunk(List<? extends W> items) {
+		this(items, null);
+	}
+
+	public Chunk(List<? extends W> items, List<SkipWrapper<W>> skips) {
+		super();
+		if (items != null) {
+			this.items = new ArrayList<>(items);
+		}
+		if (skips != null) {
+			this.skips = new ArrayList<>(skips);
+		}
+	}
+
+	/**
+	 * Add the item to the chunk.
+	 * @param item the item to add
+	 */
+	public void add(W item) {
+		items.add(item);
+	}
+
+	/**
+	 * Add all items to the chunk.
+	 * @param items the items to add
+	 */
+	public void addAll(List<W> items) {
+		this.items.addAll(items);
+	}
+
+	/**
+	 * Clear the items down to signal that we are done.
+	 */
+	public void clear() {
+		items.clear();
+		skips.clear();
+		userData = null;
+	}
+
+	/**
+	 * @return a copy of the items to be processed as an unmodifiable list
+	 */
+	public List<W> getItems() {
+		return Collections.unmodifiableList(new ArrayList<>(items));
+	}
+
+	/**
+	 * @return a copy of the skips as an unmodifiable list
+	 */
+	public List<SkipWrapper<W>> getSkips() {
+		return Collections.unmodifiableList(skips);
+	}
+
+	/**
+	 * @return a copy of the anonymous errors as an unmodifiable list
+	 */
+	public List<Exception> getErrors() {
+		return Collections.unmodifiableList(errors);
+	}
+
+	/**
+	 * Register an anonymous skip. To skip an individual item, use
+	 * {@link ChunkIterator#remove()}.
+	 * @param e the exception that caused the skip
+	 */
+	public void skip(Exception e) {
+		errors.add(e);
+	}
+
+	/**
+	 * @return true if there are no items in the chunk
+	 */
+	public boolean isEmpty() {
+		return items.isEmpty();
+	}
+
+	/**
+	 * Get an unmodifiable iterator for the underlying items.
+	 * @see java.lang.Iterable#iterator()
+	 */
+	@Override
+	public ChunkIterator iterator() {
+		return new ChunkIterator(items);
+	}
+
+	/**
+	 * @return the number of items (excluding skips)
+	 */
+	public int size() {
+		return items.size();
+	}
+
+	/**
+	 * Flag to indicate if the source data is exhausted.
+	 * @return true if there is no more data to process
+	 */
+	public boolean isEnd() {
+		return end;
+	}
+
+	/**
+	 * Set the flag to say that this chunk represents an end of stream (there is no more
+	 * data to process).
+	 */
+	public void setEnd() {
+		this.end = true;
+	}
+
+	/**
+	 * Query the chunk to see if anyone has registered an interest in keeping a reference
+	 * to it.
+	 * @return the busy flag
+	 */
+	public boolean isBusy() {
+		return busy;
+	}
+
+	/**
+	 * Register an interest in the chunk to prevent it from being cleaned up before the
+	 * flag is reset to false.
+	 * @param busy the flag to set
+	 */
+	public void setBusy(boolean busy) {
+		this.busy = busy;
+	}
+
+	/**
+	 * Clear only the skips list.
+	 */
+	public void clearSkips() {
+		skips.clear();
+	}
+
+	public Object getUserData() {
+		return userData;
+	}
+
+	public void setUserData(Object userData) {
+		this.userData = userData;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 *
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return String.format("[items=%s, skips=%s]", items, skips);
+	}
+
+	/**
+	 * Special iterator for a chunk providing the {@link #remove(Throwable)} method for
+	 * dynamically removing an item and adding it to the skips.
+	 *
+	 * @author Dave Syer
+	 *
+	 */
+	public class ChunkIterator implements Iterator<W> {
+
+		final private Iterator<W> iterator;
+
+		private W next;
+
+		public ChunkIterator(List<W> items) {
+			iterator = items.iterator();
+		}
+
+		@Override
+		public boolean hasNext() {
+			return iterator.hasNext();
+		}
+
+		@Override
+		public W next() {
+			next = iterator.next();
+			return next;
+		}
+
+		public void remove(Throwable e) {
+			remove();
+			skips.add(new SkipWrapper<>(next, e));
+		}
+
+		@Override
+		public void remove() {
+			if (next == null) {
+				if (iterator.hasNext()) {
+					next = iterator.next();
+				}
+				else {
+					return;
+				}
+			}
+			iterator.remove();
+		}
+
+		@Override
+		public String toString() {
+			return String.format("[items=%s, skips=%s]", items, skips);
+		}
+
+	}
+
+}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/ItemWriter.java

@@ -18,6 +18,8 @@ package org.springframework.batch.item;
 
 import java.util.List;
 
+import org.springframework.lang.NonNull;
+
 /**
  * <p>
  * Basic interface for generic output operations. Class implementing this interface will
@@ -36,6 +38,7 @@ import java.util.List;
  * @author Dave Syer
  * @author Lucas Ward
  * @author Taeik Lim
+ * @author Mahmoud Ben Hassine
  */
 @FunctionalInterface
 public interface ItemWriter<T> {
@@ -43,10 +46,10 @@ public interface ItemWriter<T> {
 	/**
 	 * Process the supplied data element. Will not be called with any null items in normal
 	 * operation.
-	 * @param items items to be written
+	 * @param chunk of items to be written. Must not be {@code null}.
 	 * @throws Exception if there are errors. The framework will catch the exception and
 	 * convert or rethrow it as appropriate.
 	 */
-	void write(List<? extends T> items) throws Exception;
+	void write(@NonNull Chunk<? extends T> chunk) throws Exception;
 
 }

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/KeyValueItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
@@ -23,6 +23,7 @@ import org.springframework.util.Assert;
  * a {@link Converter} to derive a key from an item
  *
  * @author David Turanski
+ * @author Mahmoud Ben Hassine
  * @since 2.2
  *
  */
@@ -38,7 +39,7 @@ public abstract class KeyValueItemWriter<K, V> implements ItemWriter<V>, Initial
 	 * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
 	 */
 	@Override
-	public void write(List<? extends V> items) throws Exception {
+	public void write(Chunk<? extends V> items) throws Exception {
 		if (items == null) {
 			return;
 		}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/SkipWrapper.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2006-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.batch.item;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * Wrapper for an item and its exception if it failed processing.
+ *
+ * @author Dave Syer
+ * @author Mahmoud Ben Hassine
+ *
+ */
+public class SkipWrapper<T> {
+
+	final private Throwable exception;
+
+	final private T item;
+
+	/**
+	 * @param item the item being wrapped.
+	 */
+	public SkipWrapper(T item) {
+		this(item, null);
+	}
+
+	/**
+	 * @param e instance of {@link Throwable} that being wrapped.
+	 */
+	public SkipWrapper(Throwable e) {
+		this(null, e);
+	}
+
+	public SkipWrapper(T item, @Nullable Throwable e) {
+		this.item = item;
+		this.exception = e;
+	}
+
+	/**
+	 * Public getter for the exception.
+	 * @return the exception
+	 */
+	@Nullable
+	public Throwable getException() {
+		return exception;
+	}
+
+	/**
+	 * Public getter for the item.
+	 * @return the item
+	 */
+	public T getItem() {
+		return item;
+	}
+
+	@Override
+	public String toString() {
+		return String.format("[exception=%s, item=%s]", exception, item);
+	}
+
+}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/adapter/ItemWriterAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2013 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.batch.item.adapter;
 
 import java.util.List;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 
 /**
@@ -26,11 +27,12 @@ import org.springframework.batch.item.ItemWriter;
  *
  * @see PropertyExtractingDelegatingItemWriter
  * @author Robert Kasanicky
+ * @author Mahmoud Ben Hassine
  */
 public class ItemWriterAdapter<T> extends AbstractMethodInvokingDelegator<T> implements ItemWriter<T> {
 
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> items) throws Exception {
 		for (T item : items) {
 			invokeDelegateMethodWithArgument(item);
 		}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/adapter/PropertyExtractingDelegatingItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2013 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.batch.item.adapter;
 import java.util.Arrays;
 import java.util.List;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.BeanWrapperImpl;
@@ -30,6 +31,7 @@ import org.springframework.util.Assert;
  *
  * @see ItemWriterAdapter
  * @author Robert Kasanicky
+ * @author Mahmoud Ben Hassine
  */
 public class PropertyExtractingDelegatingItemWriter<T> extends AbstractMethodInvokingDelegator<T>
 		implements ItemWriter<T> {
@@ -41,7 +43,7 @@ public class PropertyExtractingDelegatingItemWriter<T> extends AbstractMethodInv
 	 * passes them as arguments to the delegate method.
 	 */
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> items) throws Exception {
 		for (T item : items) {
 
 			// helper for extracting property values from a bean

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/amqp/AmqpItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.batch.item.amqp;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.amqp.core.AmqpTemplate;
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.util.Assert;
 
@@ -47,7 +48,7 @@ public class AmqpItemWriter<T> implements ItemWriter<T> {
 	}
 
 	@Override
-	public void write(final List<? extends T> items) throws Exception {
+	public void write(final Chunk<? extends T> items) throws Exception {
 		if (log.isDebugEnabled()) {
 			log.debug("Writing to AMQP with " + items.size() + " items.");
 		}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/avro/AvroItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2021 the original author or authors.
+ * Copyright 2019-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,6 +31,7 @@ import org.apache.avro.reflect.ReflectDatumWriter;
 import org.apache.avro.specific.SpecificDatumWriter;
 import org.apache.avro.specific.SpecificRecordBase;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.batch.item.ItemWriter;
@@ -84,7 +85,7 @@ public class AvroItemWriter<T> extends AbstractItemStreamItemWriter<T> {
 	}
 
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> items) throws Exception {
 		items.forEach(item -> {
 			try {
 				if (this.dataFileWriter != null) {

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/data/MongoItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,6 +22,7 @@ import java.util.List;
 import org.bson.Document;
 import org.bson.types.ObjectId;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.data.mongodb.core.BulkOperations;
@@ -113,39 +114,39 @@ public class MongoItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	 * If a transaction is active, buffer items to be written just before commit.
 	 * Otherwise write items using the provided template.
 	 *
-	 * @see org.springframework.batch.item.ItemWriter#write(List)
+	 * @see org.springframework.batch.item.ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> chunk) throws Exception {
 		if (!transactionActive()) {
-			doWrite(items);
+			doWrite(chunk);
 			return;
 		}
 
-		List<T> bufferedItems = getCurrentBuffer();
-		bufferedItems.addAll(items);
+		Chunk bufferedItems = getCurrentBuffer();
+		bufferedItems.addAll(chunk.getItems());
 	}
 
 	/**
 	 * Performs the actual write to the store via the template. This can be overridden by
 	 * a subclass if necessary.
-	 * @param items the list of items to be persisted.
+	 * @param chunk the chunk of items to be persisted.
 	 */
-	protected void doWrite(List<? extends T> items) {
-		if (!CollectionUtils.isEmpty(items)) {
+	protected void doWrite(Chunk<? extends T> chunk) {
+		if (!CollectionUtils.isEmpty(chunk.getItems())) {
 			if (this.delete) {
-				delete(items);
+				delete(chunk);
 			}
 			else {
-				saveOrUpdate(items);
+				saveOrUpdate(chunk);
 			}
 		}
 	}
 
-	private void delete(List<? extends T> items) {
-		BulkOperations bulkOperations = initBulkOperations(BulkMode.ORDERED, items.get(0));
+	private void delete(Chunk<? extends T> chunk) {
+		BulkOperations bulkOperations = initBulkOperations(BulkMode.ORDERED, chunk.getItems().get(0));
 		MongoConverter mongoConverter = this.template.getConverter();
-		for (Object item : items) {
+		for (Object item : chunk) {
 			Document document = new Document();
 			mongoConverter.write(item, document);
 			Object objectId = document.get(ID_KEY);
@@ -157,11 +158,11 @@ public class MongoItemWriter<T> implements ItemWriter<T>, InitializingBean {
 		bulkOperations.execute();
 	}
 
-	private void saveOrUpdate(List<? extends T> items) {
-		BulkOperations bulkOperations = initBulkOperations(BulkMode.ORDERED, items.get(0));
+	private void saveOrUpdate(Chunk<? extends T> chunk) {
+		BulkOperations bulkOperations = initBulkOperations(BulkMode.ORDERED, chunk.getItems().get(0));
 		MongoConverter mongoConverter = this.template.getConverter();
 		FindAndReplaceOptions upsert = new FindAndReplaceOptions().upsert();
-		for (Object item : items) {
+		for (Object item : chunk) {
 			Document document = new Document();
 			mongoConverter.write(item, document);
 			Object objectId = document.get(ID_KEY) != null ? document.get(ID_KEY) : new ObjectId();
@@ -186,19 +187,18 @@ public class MongoItemWriter<T> implements ItemWriter<T>, InitializingBean {
 		return TransactionSynchronizationManager.isActualTransactionActive();
 	}
 
-	@SuppressWarnings("unchecked")
-	private List<T> getCurrentBuffer() {
+	private Chunk<T> getCurrentBuffer() {
 		if (!TransactionSynchronizationManager.hasResource(bufferKey)) {
-			TransactionSynchronizationManager.bindResource(bufferKey, new ArrayList<T>());
+			TransactionSynchronizationManager.bindResource(bufferKey, new Chunk<T>());
 
 			TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronization() {
 				@Override
 				public void beforeCommit(boolean readOnly) {
-					List<T> items = (List<T>) TransactionSynchronizationManager.getResource(bufferKey);
+					Chunk<T> chunk = (Chunk<T>) TransactionSynchronizationManager.getResource(bufferKey);
 
-					if (!CollectionUtils.isEmpty(items)) {
+					if (!CollectionUtils.isEmpty(chunk.getItems())) {
 						if (!readOnly) {
-							doWrite(items);
+							doWrite(chunk);
 						}
 					}
 				}
@@ -212,7 +212,7 @@ public class MongoItemWriter<T> implements ItemWriter<T>, InitializingBean {
 			});
 		}
 
-		return (List<T>) TransactionSynchronizationManager.getResource(bufferKey);
+		return (Chunk<T>) TransactionSynchronizationManager.getResource(bufferKey);
 	}
 
 	@Override

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/data/Neo4jItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import org.apache.commons.logging.LogFactory;
 import org.neo4j.ogm.session.Session;
 import org.neo4j.ogm.session.SessionFactory;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.util.Assert;
@@ -86,12 +87,12 @@ public class Neo4jItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	/**
 	 * Write all items to the data store.
 	 *
-	 * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
+	 * @see org.springframework.batch.item.ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends T> items) throws Exception {
-		if (!CollectionUtils.isEmpty(items)) {
-			doWrite(items);
+	public void write(Chunk<? extends T> chunk) throws Exception {
+		if (!CollectionUtils.isEmpty(chunk.getItems())) {
+			doWrite(chunk);
 		}
 	}
 
@@ -100,7 +101,7 @@ public class Neo4jItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	 * if necessary.
 	 * @param items the list of items to be persisted.
 	 */
-	protected void doWrite(List<? extends T> items) {
+	protected void doWrite(Chunk<? extends T> items) {
 		if (delete) {
 			delete(items);
 		}
@@ -109,7 +110,7 @@ public class Neo4jItemWriter<T> implements ItemWriter<T>, InitializingBean {
 		}
 	}
 
-	private void delete(List<? extends T> items) {
+	private void delete(Chunk<? extends T> items) {
 		Session session = this.sessionFactory.openSession();
 
 		for (T item : items) {
@@ -117,7 +118,7 @@ public class Neo4jItemWriter<T> implements ItemWriter<T>, InitializingBean {
 		}
 	}
 
-	private void save(List<? extends T> items) {
+	private void save(Chunk<? extends T> items) {
 		Session session = this.sessionFactory.openSession();
 
 		for (T item : items) {

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/data/RepositoryItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,8 @@ import java.util.List;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.item.adapter.AbstractMethodInvokingDelegator.InvocationTargetThrowableWrapper;
 import org.springframework.batch.item.adapter.DynamicMethodInvocationException;
@@ -87,12 +89,12 @@ public class RepositoryItemWriter<T> implements ItemWriter<T>, InitializingBean
 	/**
 	 * Write all items to the data store via a Spring Data repository.
 	 *
-	 * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
+	 * @see org.springframework.batch.item.ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends T> items) throws Exception {
-		if (!CollectionUtils.isEmpty(items)) {
-			doWrite(items);
+	public void write(Chunk<? extends T> chunk) throws Exception {
+		if (!CollectionUtils.isEmpty(chunk.getItems())) {
+			doWrite(chunk);
 		}
 	}
 
@@ -102,7 +104,7 @@ public class RepositoryItemWriter<T> implements ItemWriter<T>, InitializingBean
 	 * @param items the list of items to be persisted.
 	 * @throws Exception thrown if error occurs during writing.
 	 */
-	protected void doWrite(List<? extends T> items) throws Exception {
+	protected void doWrite(Chunk<? extends T> items) throws Exception {
 		if (logger.isDebugEnabled()) {
 			logger.debug("Writing to the repository with " + items.size() + " items.");
 		}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/database/HibernateItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2021 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,7 @@ import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.context.spi.CurrentSessionContext;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.util.Assert;
@@ -81,10 +82,10 @@ public class HibernateItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	 * Save or update any entities not in the current hibernate session and then flush the
 	 * hibernate session.
 	 *
-	 * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
+	 * @see org.springframework.batch.item.ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends T> items) {
+	public void write(Chunk<? extends T> items) {
 		doWrite(sessionFactory, items);
 		sessionFactory.getCurrentSession().flush();
 		if (clearSession) {
@@ -98,7 +99,7 @@ public class HibernateItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	 * @param sessionFactory Hibernate SessionFactory to be used
 	 * @param items the list of items to use for the write
 	 */
-	protected void doWrite(SessionFactory sessionFactory, List<? extends T> items) {
+	protected void doWrite(SessionFactory sessionFactory, Chunk<? extends T> items) {
 		if (logger.isDebugEnabled()) {
 			logger.debug("Writing to Hibernate with " + items.size() + " items.");
 		}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/database/JdbcBatchItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2021 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,7 @@ import javax.sql.DataSource;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.dao.DataAccessException;
@@ -51,7 +52,7 @@ import org.springframework.util.Assert;
  * be responsible for mapping the item to the parameters needed to execute the SQL
  * statement.<br>
  *
- * It is expected that {@link #write(List)} is called inside a transaction.<br>
+ * It is expected that {@link #write(Chunk)} is called inside a transaction.<br>
  *
  * The writer is thread-safe after its properties are set (normal singleton behavior), so
  * it can be used to write in multiple concurrent transactions.
@@ -59,6 +60,7 @@ import org.springframework.util.Assert;
  * @author Dave Syer
  * @author Thomas Risberg
  * @author Michael Minella
+ * @author Mahmoud Ben Hassine
  * @since 2.0
  */
 public class JdbcBatchItemWriter<T> implements ItemWriter<T>, InitializingBean {
@@ -164,24 +166,25 @@ public class JdbcBatchItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	 */
 	@SuppressWarnings("unchecked")
 	@Override
-	public void write(final List<? extends T> items) throws Exception {
+	public void write(final Chunk<? extends T> chunk) throws Exception {
 
-		if (!items.isEmpty()) {
+		if (!chunk.isEmpty()) {
 
 			if (logger.isDebugEnabled()) {
-				logger.debug("Executing batch with " + items.size() + " items.");
+				logger.debug("Executing batch with " + chunk.size() + " items.");
 			}
 
 			int[] updateCounts;
 
 			if (usingNamedParameters) {
-				if (items.get(0) instanceof Map && this.itemSqlParameterSourceProvider == null) {
-					updateCounts = namedParameterJdbcTemplate.batchUpdate(sql, items.toArray(new Map[items.size()]));
+				if (chunk.getItems().get(0) instanceof Map && this.itemSqlParameterSourceProvider == null) {
+					updateCounts = namedParameterJdbcTemplate.batchUpdate(sql,
+							chunk.getItems().toArray(new Map[chunk.size()]));
 				}
 				else {
-					SqlParameterSource[] batchArgs = new SqlParameterSource[items.size()];
+					SqlParameterSource[] batchArgs = new SqlParameterSource[chunk.size()];
 					int i = 0;
-					for (T item : items) {
+					for (T item : chunk) {
 						batchArgs[i++] = itemSqlParameterSourceProvider.createSqlParameterSource(item);
 					}
 					updateCounts = namedParameterJdbcTemplate.batchUpdate(sql, batchArgs);
@@ -193,7 +196,7 @@ public class JdbcBatchItemWriter<T> implements ItemWriter<T>, InitializingBean {
 							@Override
 							public int[] doInPreparedStatement(PreparedStatement ps)
 									throws SQLException, DataAccessException {
-								for (T item : items) {
+								for (T item : chunk) {
 									itemPreparedStatementSetter.setValues(item, ps);
 									ps.addBatch();
 								}
@@ -207,7 +210,7 @@ public class JdbcBatchItemWriter<T> implements ItemWriter<T>, InitializingBean {
 					int value = updateCounts[i];
 					if (value == 0) {
 						throw new EmptyResultDataAccessException("Item " + i + " of " + updateCounts.length
-								+ " did not update any rows: [" + items.get(i) + "]", 1);
+								+ " did not update any rows: [" + chunk.getItems().get(i) + "]", 1);
 					}
 				}
 			}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/database/JpaItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2021 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,8 @@ package org.springframework.batch.item.database;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.dao.DataAccessResourceFailureException;
@@ -32,7 +34,7 @@ import java.util.List;
  * {@link org.springframework.batch.item.ItemWriter} that is using a JPA
  * EntityManagerFactory to merge any Entities that aren't part of the persistence context.
  *
- * It is required that {@link #write(List)} is called inside a transaction.<br>
+ * It is required that {@link #write(Chunk)} is called inside a transaction.<br>
  *
  * The reader must be configured with an {@link jakarta.persistence.EntityManagerFactory}
  * that is capable of participating in Spring managed transactions.
@@ -80,10 +82,10 @@ public class JpaItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	 * Merge all provided items that aren't already in the persistence context and then
 	 * flush the entity manager.
 	 *
-	 * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
+	 * @see org.springframework.batch.item.ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends T> items) {
+	public void write(Chunk<? extends T> items) {
 		EntityManager entityManager = EntityManagerFactoryUtils.getTransactionalEntityManager(entityManagerFactory);
 		if (entityManager == null) {
 			throw new DataAccessResourceFailureException("Unable to obtain a transactional EntityManager");
@@ -98,7 +100,7 @@ public class JpaItemWriter<T> implements ItemWriter<T>, InitializingBean {
 	 * @param entityManager the EntityManager to use for the operation
 	 * @param items the list of items to use for the write
 	 */
-	protected void doWrite(EntityManager entityManager, List<? extends T> items) {
+	protected void doWrite(EntityManager entityManager, Chunk<? extends T> items) {
 
 		if (logger.isDebugEnabled()) {
 			logger.debug("Writing to JPA with " + items.size() + " items.");

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/FlatFileItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2018 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.batch.item.file;
 
 import java.util.List;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.file.transform.LineAggregator;
 import org.springframework.batch.item.support.AbstractFileItemWriter;
 import org.springframework.core.io.Resource;
@@ -71,7 +72,7 @@ public class FlatFileItemWriter<T> extends AbstractFileItemWriter<T> {
 	}
 
 	@Override
-	public String doWrite(List<? extends T> items) {
+	public String doWrite(Chunk<? extends T> items) {
 		StringBuilder lines = new StringBuilder();
 		for (T item : items) {
 			lines.append(this.lineAggregator.aggregate(item)).append(this.lineSeparator);

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/MultiResourceItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2017 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,8 @@ package org.springframework.batch.item.file;
 import java.io.File;
 import java.io.IOException;
 import java.util.List;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.batch.item.support.AbstractItemStreamItemWriter;
@@ -39,6 +41,7 @@ import org.springframework.util.ClassUtils;
  *
  * @param <T> item type
  * @author Robert Kasanicky
+ * @author Mahmoud Ben Hassine
  */
 public class MultiResourceItemWriter<T> extends AbstractItemStreamItemWriter<T> {
 
@@ -67,7 +70,7 @@ public class MultiResourceItemWriter<T> extends AbstractItemStreamItemWriter<T>
 	}
 
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> items) throws Exception {
 		if (!opened) {
 			File file = setResourceToDelegate();
 			// create only if write is called

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/jms/JmsItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,8 @@ package org.springframework.batch.item.jms;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.jms.core.JmsOperations;
 import org.springframework.jms.core.JmsTemplate;
@@ -27,13 +29,14 @@ import java.util.List;
 
 /**
  * An {@link ItemWriter} for JMS using a {@link JmsTemplate}. The template should have a
- * default destination, which will be used to send items in {@link #write(List)}.<br>
+ * default destination, which will be used to send items in {@link #write(Chunk)}.<br>
  * <br>
  *
  * The implementation is thread-safe after its properties are set (normal singleton
  * behavior).
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  *
  */
 public class JmsItemWriter<T> implements ItemWriter<T> {
@@ -58,10 +61,10 @@ public class JmsItemWriter<T> implements ItemWriter<T> {
 	/**
 	 * Send the items one-by-one to the default destination of the JMS template.
 	 *
-	 * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
+	 * @see org.springframework.batch.item.ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> items) throws Exception {
 
 		if (logger.isDebugEnabled()) {
 			logger.debug("Writing to JMS with " + items.size() + " items.");

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/json/JsonFileItemWriter.java

@@ -19,6 +19,7 @@ package org.springframework.batch.item.json;
 import java.util.Iterator;
 import java.util.List;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.support.AbstractFileItemWriter;
 import org.springframework.core.io.WritableResource;
 import org.springframework.util.Assert;
@@ -94,7 +95,7 @@ public class JsonFileItemWriter<T> extends AbstractFileItemWriter<T> {
 	}
 
 	@Override
-	public String doWrite(List<? extends T> items) {
+	public String doWrite(Chunk<? extends T> items) {
 		StringBuilder lines = new StringBuilder();
 		Iterator<? extends T> iterator = items.iterator();
 		if (!items.isEmpty() && state.getLinesWritten() > 0) {

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/mail/SimpleMailMessageItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2010 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.mail.MailException;
@@ -50,6 +51,7 @@ import org.springframework.util.Assert;
  * </p>
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.1
  *
  */
@@ -60,7 +62,7 @@ public class SimpleMailMessageItemWriter implements ItemWriter<SimpleMailMessage
 	private MailErrorHandler mailErrorHandler = new DefaultMailErrorHandler();
 
 	/**
-	 * A {@link MailSender} to be used to send messages in {@link #write(List)}.
+	 * A {@link MailSender} to be used to send messages in {@link #write(Chunk)}.
 	 * @param mailSender The {@link MailSender} to be used.
 	 */
 	public void setMailSender(MailSender mailSender) {
@@ -87,13 +89,13 @@ public class SimpleMailMessageItemWriter implements ItemWriter<SimpleMailMessage
 	}
 
 	/**
-	 * @param items the items to send
-	 * @see ItemWriter#write(List)
+	 * @param chunk the chunk of items to send
+	 * @see ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends SimpleMailMessage> items) throws MailException {
+	public void write(Chunk<? extends SimpleMailMessage> chunk) throws MailException {
 		try {
-			mailSender.send(items.toArray(new SimpleMailMessage[items.size()]));
+			mailSender.send(chunk.getItems().toArray(new SimpleMailMessage[chunk.size()]));
 		}
 		catch (MailSendException e) {
 			Map<Object, Exception> failedMessages = e.getFailedMessages();

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/mail/builder/SimpleMailMessageItemWriterBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 the original author or authors.
+ * Copyright 2017-2022 the original author or authors.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -28,6 +28,7 @@ import org.springframework.util.Assert;
  * Creates a fully qualified SimpleMailMessageItemWriter.
  *
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  * @since 4.0
  */
 
@@ -39,7 +40,7 @@ public class SimpleMailMessageItemWriterBuilder {
 
 	/**
 	 * A {@link MailSender} to be used to send messages in
-	 * {@link SimpleMailMessageItemWriter#write(List)}.
+	 * {@link SimpleMailMessageItemWriter#write(Chunk)}.
 	 * @param mailSender strategy for sending simple mails.
 	 * @return this instance for method chaining.
 	 * @see SimpleMailMessageItemWriter#setMailSender(MailSender)

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/mail/javamail/MimeMessageItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2021 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.springframework.batch.item.mail.javamail;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.item.mail.DefaultMailErrorHandler;
 import org.springframework.batch.item.mail.MailErrorHandler;
@@ -64,7 +65,7 @@ public class MimeMessageItemWriter implements ItemWriter<MimeMessage> {
 	private MailErrorHandler mailErrorHandler = new DefaultMailErrorHandler();
 
 	/**
-	 * A {@link JavaMailSender} to be used to send messages in {@link #write(List)}.
+	 * A {@link JavaMailSender} to be used to send messages in {@link #write(Chunk)}.
 	 * @param mailSender service for doing the work of sending a MIME message
 	 */
 	public void setJavaMailSender(JavaMailSender mailSender) {
@@ -90,13 +91,13 @@ public class MimeMessageItemWriter implements ItemWriter<MimeMessage> {
 	}
 
 	/**
-	 * @param items the items to send
-	 * @see ItemWriter#write(List)
+	 * @param chunk the chunk of items to send
+	 * @see ItemWriter#write(Chunk)
 	 */
 	@Override
-	public void write(List<? extends MimeMessage> items) throws MailException {
+	public void write(Chunk<? extends MimeMessage> chunk) throws MailException {
 		try {
-			mailSender.send(items.toArray(new MimeMessage[items.size()]));
+			mailSender.send(chunk.getItems().toArray(new MimeMessage[chunk.size()]));
 		}
 		catch (MailSendException e) {
 			Map<Object, Exception> failedMessages = e.getFailedMessages();

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/AbstractFileItemWriter.java

@@ -31,6 +31,7 @@ import java.util.List;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStream;
 import org.springframework.batch.item.ItemStreamException;
@@ -220,7 +221,7 @@ public abstract class AbstractFileItemWriter<T> extends AbstractItemStreamItemWr
 	 * @throws Exception if an error occurs while writing items to the output stream
 	 */
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> items) throws Exception {
 		if (!getOutputState().isInitialized()) {
 			throw new WriterNotOpenException("Writer must be open before it can be written to");
 		}
@@ -247,7 +248,7 @@ public abstract class AbstractFileItemWriter<T> extends AbstractItemStreamItemWr
 	 * @param items to be written
 	 * @return written lines
 	 */
-	protected abstract String doWrite(List<? extends T> items);
+	protected abstract String doWrite(Chunk<? extends T> items);
 
 	/**
 	 * @see ItemStream#close()

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/ClassifierCompositeItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.classify.Classifier;
 import org.springframework.classify.ClassifierSupport;
 import org.springframework.batch.item.ItemWriter;
@@ -34,6 +35,7 @@ import org.springframework.util.Assert;
  *
  * @author Dave Syer
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  * @since 2.0
  */
 public class ClassifierCompositeItemWriter<T> implements ItemWriter<T> {
@@ -53,14 +55,14 @@ public class ClassifierCompositeItemWriter<T> implements ItemWriter<T> {
 	 * classification by the {@link Classifier}.
 	 */
 	@Override
-	public void write(List<? extends T> items) throws Exception {
+	public void write(Chunk<? extends T> items) throws Exception {
 
-		Map<ItemWriter<? super T>, List<T>> map = new LinkedHashMap<>();
+		Map<ItemWriter<? super T>, Chunk<T>> map = new LinkedHashMap<>();
 
 		for (T item : items) {
 			ItemWriter<? super T> key = classifier.classify(item);
 			if (!map.containsKey(key)) {
-				map.put(key, new ArrayList<>());
+				map.put(key, new Chunk<>());
 			}
 			map.get(key).add(item);
 		}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/CompositeItemWriter.java

@@ -16,6 +16,7 @@
 
 package org.springframework.batch.item.support;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStream;
 import org.springframework.batch.item.ItemStreamException;
@@ -35,6 +36,7 @@ import java.util.List;
  *
  * @author Robert Kasanicky
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  */
 public class CompositeItemWriter<T> implements ItemStreamWriter<T>, InitializingBean {
 
@@ -78,9 +80,9 @@ public class CompositeItemWriter<T> implements ItemStreamWriter<T>, Initializing
 	}
 
 	@Override
-	public void write(List<? extends T> item) throws Exception {
+	public void write(Chunk<? extends T> chunk) throws Exception {
 		for (ItemWriter<? super T> writer : delegates) {
-			writer.write(item);
+			writer.write(chunk);
 		}
 	}
 

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/ListItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2019 the original author or authors.
+ * Copyright 2014-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.springframework.batch.item.support;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 
 import java.util.ArrayList;
@@ -22,14 +23,15 @@ import java.util.List;
 
 /**
  * @author mminella
+ * @author Mahmoud Ben Hassine
  */
 public class ListItemWriter<T> implements ItemWriter<T> {
 
 	private List<T> writtenItems = new ArrayList<>();
 
 	@Override
-	public void write(List<? extends T> items) throws Exception {
-		writtenItems.addAll(items);
+	public void write(Chunk<? extends T> chunk) throws Exception {
+		writtenItems.addAll(chunk.getItems());
 	}
 
 	public List<? extends T> getWrittenItems() {

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/SynchronizedItemStreamWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020 the original author or authors.
+ * Copyright 2020-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.springframework.batch.item.support;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.batch.item.ItemStreamWriter;
@@ -60,7 +61,7 @@ public class SynchronizedItemStreamWriter<T> implements ItemStreamWriter<T>, Ini
 	 * This method delegates to the {@code write} method of the {@code delegate}.
 	 */
 	@Override
-	public synchronized void write(List<? extends T> items) throws Exception {
+	public synchronized void write(Chunk<? extends T> items) throws Exception {
 		this.delegate.write(items);
 	}
 

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/xml/StaxEventItemWriter.java

@@ -38,6 +38,7 @@ import javax.xml.transform.Result;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.batch.item.ItemWriter;
@@ -761,7 +762,7 @@ public class StaxEventItemWriter<T> extends AbstractItemStreamItemWriter<T>
 	 * @throws XmlMappingException thrown if error occurs during XML Mapping.
 	 */
 	@Override
-	public void write(List<? extends T> items) throws XmlMappingException, IOException {
+	public void write(Chunk<? extends T> items) throws XmlMappingException, IOException {
 
 		if (!this.initialized) {
 			throw new WriterNotOpenException("Writer must be open before it can be written to");

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/adapter/ItemWriterAdapterTests.java

@@ -23,6 +23,8 @@ import java.util.ArrayList;
 import java.util.List;
 
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.item.sample.Foo;
 import org.springframework.batch.item.sample.FooService;
@@ -33,6 +35,7 @@ import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
  * Tests for {@link ItemWriterAdapter}.
  *
  * @author Robert Kasanicky
+ * @author Mahmoud Ben Hassine
  */
 @SpringJUnitConfig(locations = "delegating-item-writer.xml")
 class ItemWriterAdapterTests {
@@ -50,7 +53,7 @@ class ItemWriterAdapterTests {
 	@Test
 	void testProcess() throws Exception {
 		Foo foo;
-		List<Foo> foos = new ArrayList<>();
+		Chunk<Foo> foos = new Chunk<>();
 		while ((foo = fooService.generateFoo()) != null) {
 			foos.add(foo);
 		}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/adapter/PropertyExtractingDelegatingItemProcessorIntegrationTests.java

@@ -21,6 +21,7 @@ import org.junit.jupiter.api.Test;
 import java.util.Collections;
 import java.util.List;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.sample.Foo;
 import org.springframework.batch.item.sample.FooService;
 import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
@@ -49,7 +50,7 @@ class PropertyExtractingDelegatingItemProcessorIntegrationTests {
 	void testProcess() throws Exception {
 		Foo foo;
 		while ((foo = fooService.generateFoo()) != null) {
-			processor.write(Collections.singletonList(foo));
+			processor.write(Chunk.of(foo));
 		}
 
 		List<Foo> input = fooService.getGeneratedFoos();

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/amqp/AmqpItemWriterTests.java

@@ -21,6 +21,7 @@ import static org.mockito.Mockito.mock;
 
 import org.junit.jupiter.api.Test;
 import org.springframework.amqp.core.AmqpTemplate;
+import org.springframework.batch.item.Chunk;
 
 import java.util.Arrays;
 
@@ -31,6 +32,7 @@ import java.util.Arrays;
  *
  * @author Chris Schaefer
  * @author Will Schipp
+ * @author Mahmoud Ben Hassine
  */
 class AmqpItemWriterTests {
 
@@ -48,7 +50,7 @@ class AmqpItemWriterTests {
 		amqpTemplate.convertAndSend("bar");
 
 		AmqpItemWriter<String> amqpItemWriter = new AmqpItemWriter<>(amqpTemplate);
-		amqpItemWriter.write(Arrays.asList("foo", "bar"));
+		amqpItemWriter.write(Chunk.of("foo", "bar"));
 
 	}
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/amqp/builder/AmqpItemWriterBuilderTests.java

@@ -22,6 +22,7 @@ import org.junit.jupiter.api.Test;
 
 import org.springframework.amqp.core.AmqpTemplate;
 import org.springframework.amqp.core.Message;
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.amqp.AmqpItemWriter;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -31,6 +32,7 @@ import static org.mockito.Mockito.verify;
 
 /**
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  */
 class AmqpItemWriterBuilderTests {
 
@@ -46,7 +48,7 @@ class AmqpItemWriterBuilderTests {
 		AmqpTemplate amqpTemplate = mock(AmqpTemplate.class);
 
 		AmqpItemWriter<String> amqpItemWriter = new AmqpItemWriterBuilder<String>().amqpTemplate(amqpTemplate).build();
-		amqpItemWriter.write(Arrays.asList("foo", "bar"));
+		amqpItemWriter.write(Chunk.of("foo", "bar"));
 		verify(amqpTemplate).convertAndSend("foo");
 		verify(amqpTemplate).convertAndSend("bar");
 	}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/avro/support/AvroItemReaderTestSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 the original author or authors.
+ * Copyright 2019-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.batch.item.avro.support;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.avro.AvroItemReader;
 
@@ -26,10 +27,11 @@ import static org.assertj.core.api.Assertions.assertThat;
 
 /**
  * @author David Turanski
+ * @author Mahmoud Ben Hassine
  */
 public abstract class AvroItemReaderTestSupport extends AvroTestFixtures {
 
-	protected <T> void verify(AvroItemReader<T> avroItemReader, List<T> actual) throws Exception {
+	protected <T> void verify(AvroItemReader<T> avroItemReader, Chunk<T> actual) throws Exception {
 
 		avroItemReader.open(new ExecutionContext());
 		List<T> users = new ArrayList<>();
@@ -40,7 +42,9 @@ public abstract class AvroItemReaderTestSupport extends AvroTestFixtures {
 		}
 
 		assertThat(users).hasSize(4);
-		assertThat(users).containsExactlyInAnyOrder(actual.get(0), actual.get(1), actual.get(2), actual.get(3));
+		List<T> actualItems = actual.getItems();
+		assertThat(users).containsExactlyInAnyOrder(actualItems.get(0), actualItems.get(1), actualItems.get(2),
+				actualItems.get(3));
 
 		avroItemReader.close();
 	}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/avro/support/AvroItemWriterTestSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 the original author or authors.
+ * Copyright 2019-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,7 @@ import java.net.URL;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.avro.AvroItemReader;
 import org.springframework.batch.item.avro.builder.AvroItemReaderBuilder;
@@ -36,22 +37,23 @@ import static org.assertj.core.api.Assertions.assertThat;
 
 /**
  * @author David Turanski
+ * @author Mahmoud Ben Hassine
  */
 public abstract class AvroItemWriterTestSupport extends AvroTestFixtures {
 
 	/*
 	 * This item reader configured for Specific Avro types.
 	 */
-	protected <T> void verifyRecords(byte[] bytes, List<T> actual, Class<T> clazz, boolean embeddedSchema)
+	protected <T> void verifyRecords(byte[] bytes, Chunk<T> actual, Class<T> clazz, boolean embeddedSchema)
 			throws Exception {
 		doVerify(bytes, clazz, actual, embeddedSchema);
 	}
 
-	protected <T> void verifyRecordsWithEmbeddedHeader(byte[] bytes, List<T> actual, Class<T> clazz) throws Exception {
+	protected <T> void verifyRecordsWithEmbeddedHeader(byte[] bytes, Chunk<T> actual, Class<T> clazz) throws Exception {
 		doVerify(bytes, clazz, actual, true);
 	}
 
-	private <T> void doVerify(byte[] bytes, Class<T> clazz, List<T> actual, boolean embeddedSchema) throws Exception {
+	private <T> void doVerify(byte[] bytes, Class<T> clazz, Chunk<T> actual, boolean embeddedSchema) throws Exception {
 		AvroItemReader<T> avroItemReader = new AvroItemReaderBuilder<T>().type(clazz)
 				.resource(new ByteArrayResource(bytes)).embeddedSchema(embeddedSchema).build();
 
@@ -63,7 +65,9 @@ public abstract class AvroItemWriterTestSupport extends AvroTestFixtures {
 			records.add(record);
 		}
 		assertThat(records).hasSize(4);
-		assertThat(records).containsExactlyInAnyOrder(actual.get(0), actual.get(1), actual.get(2), actual.get(3));
+		List<T> actualItems = actual.getItems();
+		assertThat(records).containsExactlyInAnyOrder(actualItems.get(0), actualItems.get(1), actualItems.get(2),
+				actualItems.get(3));
 	}
 
 	protected static class OutputStreamResource implements WritableResource {

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/avro/support/AvroTestFixtures.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 the original author or authors.
+ * Copyright 2019-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,8 @@ import org.apache.avro.io.Encoder;
 import org.apache.avro.io.EncoderFactory;
 import org.apache.avro.reflect.ReflectData;
 import org.apache.avro.reflect.ReflectDatumWriter;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.avro.example.User;
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.ClassPathResource;
@@ -45,13 +47,13 @@ import org.springframework.core.io.Resource;
 public abstract class AvroTestFixtures {
 
 	//@formatter:off
-	private final List<User> avroGeneratedUsers = Arrays.asList(
+	private final Chunk<User> avroGeneratedUsers = Chunk.of(
 			new User("David", 20, "blue"),
 			new User("Sue", 4, "red"),
 			new User("Alana", 13, "yellow"),
 			new User("Joe", 1, "pink"));
 
-	private List<PlainOldUser> plainOldUsers = Arrays.asList(
+	private Chunk<PlainOldUser> plainOldUsers = Chunk.of(
 			new PlainOldUser("David", 20, "blue"),
 			new PlainOldUser("Sue", 4, "red"),
 			new PlainOldUser("Alana", 13, "yellow"),
@@ -86,27 +88,28 @@ public abstract class AvroTestFixtures {
 		}
 	}
 
-	protected List<User> avroGeneratedUsers() {
+	protected Chunk<User> avroGeneratedUsers() {
 		return this.avroGeneratedUsers;
 	}
 
-	protected List<GenericRecord> genericAvroGeneratedUsers() {
-		return this.avroGeneratedUsers.stream().map(u -> {
+	protected Chunk<GenericRecord> genericAvroGeneratedUsers() {
+		return new Chunk(this.avroGeneratedUsers.getItems().stream().map(u -> {
 			GenericData.Record avroRecord;
 			avroRecord = new GenericData.Record(u.getSchema());
 			avroRecord.put("name", u.getName());
 			avroRecord.put("favorite_number", u.getFavoriteNumber());
 			avroRecord.put("favorite_color", u.getFavoriteColor());
 			return avroRecord;
-		}).collect(Collectors.toList());
+		}).collect(Collectors.toList()));
 	}
 
-	protected List<PlainOldUser> plainOldUsers() {
+	protected Chunk<PlainOldUser> plainOldUsers() {
 		return this.plainOldUsers;
 	}
 
-	protected List<GenericRecord> genericPlainOldUsers() {
-		return this.plainOldUsers.stream().map(PlainOldUser::toGenericRecord).collect(Collectors.toList());
+	protected Chunk<GenericRecord> genericPlainOldUsers() {
+		return new Chunk(
+				this.plainOldUsers.getItems().stream().map(PlainOldUser::toGenericRecord).collect(Collectors.toList()));
 	}
 
 	protected static class PlainOldUser {

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/GemfireItemWriterTests.java

@@ -27,6 +27,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.SpELItemKeyMapper;
 import org.springframework.data.gemfire.GemfireTemplate;
 import org.springframework.core.convert.converter.Converter;
@@ -61,29 +63,30 @@ class GemfireItemWriterTests {
 
 	@Test
 	void testBasicWrite() throws Exception {
-		List<Foo> items = new ArrayList<Foo>() {
+		Chunk<Foo> chunk = new Chunk<Foo>() {
 			{
 				add(new Foo(new Bar("val1")));
 				add(new Foo(new Bar("val2")));
 			}
 		};
 
-		writer.write(items);
+		writer.write(chunk);
 
+		List<Foo> items = chunk.getItems();
 		verify(template).put("val1", items.get(0));
 		verify(template).put("val2", items.get(1));
 	}
 
 	@Test
 	void testBasicDelete() throws Exception {
-		List<Foo> items = new ArrayList<Foo>() {
+		Chunk<Foo> chunk = new Chunk<Foo>() {
 			{
 				add(new Foo(new Bar("val1")));
 				add(new Foo(new Bar("val2")));
 			}
 		};
 		writer.setDelete(true);
-		writer.write(items);
+		writer.write(chunk);
 
 		verify(template).remove("val1");
 		verify(template).remove("val2");
@@ -91,7 +94,7 @@ class GemfireItemWriterTests {
 
 	@Test
 	void testWriteWithCustomItemKeyMapper() throws Exception {
-		List<Foo> items = new ArrayList<Foo>() {
+		Chunk<Foo> chunk = new Chunk<Foo>() {
 			{
 				add(new Foo(new Bar("val1")));
 				add(new Foo(new Bar("val2")));
@@ -108,8 +111,9 @@ class GemfireItemWriterTests {
 			}
 		});
 		writer.afterPropertiesSet();
-		writer.write(items);
+		writer.write(chunk);
 
+		List<Foo> items = chunk.getItems();
 		verify(template).put("item1", items.get(0));
 		verify(template).put("item2", items.get(1));
 	}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/MongoItemWriterTests.java

@@ -38,6 +38,8 @@ import static org.mockito.Mockito.never;
 
 import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.support.transaction.ResourcelessTransactionManager;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mongodb.core.BulkOperations;
@@ -104,7 +106,7 @@ class MongoItemWriterTests {
 
 	@Test
 	void testWriteNoTransactionNoCollection() throws Exception {
-		List<Item> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		Chunk<Item> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		writer.write(items);
 
@@ -114,7 +116,7 @@ class MongoItemWriterTests {
 
 	@Test
 	void testWriteNoTransactionWithCollection() throws Exception {
-		List<Object> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		Chunk<Object> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		writer.setCollection("collection");
 
@@ -126,7 +128,7 @@ class MongoItemWriterTests {
 
 	@Test
 	void testWriteNoTransactionNoItems() throws Exception {
-		writer.write(null);
+		writer.write(new Chunk<>());
 
 		verifyNoInteractions(template);
 		verifyNoInteractions(bulkOperations);
@@ -134,7 +136,7 @@ class MongoItemWriterTests {
 
 	@Test
 	void testWriteTransactionNoCollection() {
-		final List<Object> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		final Chunk<Object> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		new TransactionTemplate(transactionManager).execute((TransactionCallback<Void>) status -> {
 			assertDoesNotThrow(() -> writer.write(items));
@@ -147,7 +149,7 @@ class MongoItemWriterTests {
 
 	@Test
 	void testWriteTransactionWithCollection() {
-		final List<Object> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		final Chunk<Object> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		writer.setCollection("collection");
 
@@ -162,7 +164,7 @@ class MongoItemWriterTests {
 
 	@Test
 	void testWriteTransactionFails() {
-		final List<Object> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		final Chunk<Object> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		writer.setCollection("collection");
 
@@ -183,7 +185,7 @@ class MongoItemWriterTests {
 	 */
 	@Test
 	void testWriteTransactionReadOnly() {
-		final List<Object> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		final Chunk<Object> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		writer.setCollection("collection");
 
@@ -201,7 +203,7 @@ class MongoItemWriterTests {
 	@Test
 	void testRemoveNoObjectIdNoCollection() throws Exception {
 		writer.setDelete(true);
-		List<Object> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		Chunk<Object> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		writer.write(items);
 
@@ -212,7 +214,7 @@ class MongoItemWriterTests {
 	@Test
 	void testRemoveNoObjectIdWithCollection() throws Exception {
 		writer.setDelete(true);
-		List<Object> items = Arrays.asList(new Item("Foo"), new Item("Bar"));
+		Chunk<Object> items = Chunk.of(new Item("Foo"), new Item("Bar"));
 
 		writer.setCollection("collection");
 		writer.write(items);
@@ -224,7 +226,7 @@ class MongoItemWriterTests {
 	@Test
 	void testRemoveNoTransactionNoCollection() throws Exception {
 		writer.setDelete(true);
-		List<Object> items = Arrays.asList(new Item(1), new Item(2));
+		Chunk<Object> items = Chunk.of(new Item(1), new Item(2));
 
 		writer.write(items);
 
@@ -235,7 +237,7 @@ class MongoItemWriterTests {
 	@Test
 	void testRemoveNoTransactionWithCollection() throws Exception {
 		writer.setDelete(true);
-		List<Object> items = Arrays.asList(new Item(1), new Item(2));
+		Chunk<Object> items = Chunk.of(new Item(1), new Item(2));
 
 		writer.setCollection("collection");
 
@@ -285,7 +287,7 @@ class MongoItemWriterTests {
 		new TransactionTemplate(transactionManager).execute((TransactionCallback<Void>) status -> {
 			try {
 				for (int i = 0; i < limit; i++) {
-					writers.get(i).write(Collections.singletonList(String.valueOf(i)));
+					writers.get(i).write(Chunk.of(String.valueOf(i)));
 				}
 			}
 			catch (Exception e) {

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/Neo4jItemWriterTests.java

@@ -25,6 +25,8 @@ import org.mockito.quality.Strictness;
 import org.neo4j.ogm.session.Session;
 import org.neo4j.ogm.session.SessionFactory;
 
+import org.springframework.batch.item.Chunk;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.verify;
@@ -62,32 +64,6 @@ class Neo4jItemWriterTests {
 		writer.afterPropertiesSet();
 	}
 
-	@Test
-	void testWriteNullSession() throws Exception {
-
-		writer = new Neo4jItemWriter<>();
-
-		writer.setSessionFactory(this.sessionFactory);
-		writer.afterPropertiesSet();
-
-		writer.write(null);
-
-		verifyNoInteractions(this.session);
-	}
-
-	@Test
-	void testWriteNullWithSession() throws Exception {
-		writer = new Neo4jItemWriter<>();
-
-		writer.setSessionFactory(this.sessionFactory);
-		writer.afterPropertiesSet();
-
-		when(this.sessionFactory.openSession()).thenReturn(this.session);
-		writer.write(null);
-
-		verifyNoInteractions(this.session);
-	}
-
 	@Test
 	void testWriteNoItemsWithSession() throws Exception {
 		writer = new Neo4jItemWriter<>();
@@ -96,7 +72,7 @@ class Neo4jItemWriterTests {
 		writer.afterPropertiesSet();
 
 		when(this.sessionFactory.openSession()).thenReturn(this.session);
-		writer.write(new ArrayList<>());
+		writer.write(new Chunk<>());
 
 		verifyNoInteractions(this.session);
 	}
@@ -108,7 +84,7 @@ class Neo4jItemWriterTests {
 		writer.setSessionFactory(this.sessionFactory);
 		writer.afterPropertiesSet();
 
-		List<String> items = new ArrayList<>();
+		Chunk<String> items = new Chunk<>();
 		items.add("foo");
 		items.add("bar");
 
@@ -126,7 +102,7 @@ class Neo4jItemWriterTests {
 		writer.setSessionFactory(this.sessionFactory);
 		writer.afterPropertiesSet();
 
-		List<String> items = new ArrayList<>();
+		Chunk<String> items = new Chunk<>();
 		items.add("foo");
 		items.add("bar");
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/RepositoryItemWriterTests.java

@@ -31,6 +31,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.data.repository.CrudRepository;
 
 @ExtendWith(MockitoExtension.class)
@@ -64,16 +66,14 @@ class RepositoryItemWriterTests {
 
 	@Test
 	void testWriteNoItems() throws Exception {
-		writer.write(null);
-
-		writer.write(new ArrayList<>());
+		writer.write(new Chunk<>());
 
 		verifyNoInteractions(repository);
 	}
 
 	@Test
 	void testWriteItems() throws Exception {
-		List<String> items = Collections.singletonList("foo");
+		Chunk<String> items = Chunk.of("foo");
 
 		writer.write(items);
 
@@ -83,7 +83,7 @@ class RepositoryItemWriterTests {
 
 	@Test
 	void testWriteItemsWithDefaultMethodName() throws Exception {
-		List<String> items = Collections.singletonList("foo");
+		Chunk<String> items = Chunk.of("foo");
 
 		writer.setMethodName(null);
 		writer.write(items);

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/builder/GemfireItemWriterBuilderTests.java

@@ -24,6 +24,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.SpELItemKeyMapper;
 import org.springframework.batch.item.data.GemfireItemWriter;
 import org.springframework.data.gemfire.GemfireTemplate;
@@ -35,6 +37,7 @@ import static org.mockito.Mockito.verify;
 
 /**
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  */
 @ExtendWith(MockitoExtension.class)
 class GemfireItemWriterBuilderTests {
@@ -44,11 +47,11 @@ class GemfireItemWriterBuilderTests {
 
 	private SpELItemKeyMapper<String, GemfireItemWriterBuilderTests.Foo> itemKeyMapper;
 
-	private List<GemfireItemWriterBuilderTests.Foo> items;
+	private Chunk<Foo> items;
 
 	@BeforeEach
 	void setUp() {
-		this.items = Arrays.asList(new GemfireItemWriterBuilderTests.Foo(new GemfireItemWriterBuilderTests.Bar("val1")),
+		this.items = Chunk.of(new GemfireItemWriterBuilderTests.Foo(new GemfireItemWriterBuilderTests.Bar("val1")),
 				new GemfireItemWriterBuilderTests.Foo(new GemfireItemWriterBuilderTests.Bar("val2")));
 		this.itemKeyMapper = new SpELItemKeyMapper<>("bar.val");
 	}
@@ -60,8 +63,8 @@ class GemfireItemWriterBuilderTests {
 
 		writer.write(this.items);
 
-		verify(this.template).put("val1", items.get(0));
-		verify(this.template).put("val2", items.get(1));
+		verify(this.template).put("val1", items.getItems().get(0));
+		verify(this.template).put("val2", items.getItems().get(1));
 		verify(this.template, never()).remove("val1");
 		verify(this.template, never()).remove("val2");
 	}
@@ -75,8 +78,8 @@ class GemfireItemWriterBuilderTests {
 
 		verify(this.template).remove("val1");
 		verify(this.template).remove("val2");
-		verify(this.template, never()).put("val1", items.get(0));
-		verify(this.template, never()).put("val2", items.get(1));
+		verify(this.template, never()).put("val1", items.getItems().get(0));
+		verify(this.template, never()).put("val2", items.getItems().get(1));
 	}
 
 	@Test

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/builder/MongoItemWriterBuilderTests.java

@@ -31,6 +31,8 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.data.MongoItemWriter;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mongodb.core.BulkOperations;
@@ -68,9 +70,9 @@ class MongoItemWriterBuilderTests {
 
 	private MongoConverter mongoConverter;
 
-	private List<Item> saveItems;
+	private Chunk<Item> saveItems;
 
-	private List<Item> removeItems;
+	private Chunk<Item> removeItems;
 
 	@BeforeEach
 	void setUp() {
@@ -81,8 +83,8 @@ class MongoItemWriterBuilderTests {
 		mongoConverter = spy(new MappingMongoConverter(this.dbRefResolver, mappingContext));
 		when(this.template.getConverter()).thenReturn(mongoConverter);
 
-		this.saveItems = Arrays.asList(new Item("Foo"), new Item("Bar"));
-		this.removeItems = Arrays.asList(new Item(1), new Item(2));
+		this.saveItems = Chunk.of(new Item("Foo"), new Item("Bar"));
+		this.removeItems = Chunk.of(new Item(1), new Item(2));
 	}
 
 	@Test
@@ -91,8 +93,8 @@ class MongoItemWriterBuilderTests {
 		writer.write(this.saveItems);
 
 		verify(this.template).bulkOps(any(), any(Class.class));
-		verify(this.mongoConverter).write(eq(this.saveItems.get(0)), any(Document.class));
-		verify(this.mongoConverter).write(eq(this.saveItems.get(1)), any(Document.class));
+		verify(this.mongoConverter).write(eq(this.saveItems.getItems().get(0)), any(Document.class));
+		verify(this.mongoConverter).write(eq(this.saveItems.getItems().get(1)), any(Document.class));
 		verify(this.bulkOperations, times(2)).replaceOne(any(Query.class), any(Object.class), any());
 		verify(this.bulkOperations, never()).remove(any(Query.class));
 	}
@@ -105,8 +107,8 @@ class MongoItemWriterBuilderTests {
 		writer.write(this.saveItems);
 
 		verify(this.template).bulkOps(any(), eq("collection"));
-		verify(this.mongoConverter).write(eq(this.saveItems.get(0)), any(Document.class));
-		verify(this.mongoConverter).write(eq(this.saveItems.get(1)), any(Document.class));
+		verify(this.mongoConverter).write(eq(this.saveItems.getItems().get(0)), any(Document.class));
+		verify(this.mongoConverter).write(eq(this.saveItems.getItems().get(1)), any(Document.class));
 		verify(this.bulkOperations, times(2)).replaceOne(any(Query.class), any(Object.class), any());
 		verify(this.bulkOperations, never()).remove(any(Query.class));
 	}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/builder/Neo4jItemWriterBuilderTests.java

@@ -26,6 +26,7 @@ import org.mockito.junit.jupiter.MockitoExtension;
 import org.neo4j.ogm.session.Session;
 import org.neo4j.ogm.session.SessionFactory;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.data.Neo4jItemWriter;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -36,6 +37,7 @@ import static org.mockito.Mockito.when;
 
 /**
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  */
 @SuppressWarnings("deprecation")
 @ExtendWith(MockitoExtension.class)
@@ -51,7 +53,7 @@ class Neo4jItemWriterBuilderTests {
 	void testBasicWriter() throws Exception {
 		Neo4jItemWriter<String> writer = new Neo4jItemWriterBuilder<String>().sessionFactory(this.sessionFactory)
 				.build();
-		List<String> items = new ArrayList<>();
+		Chunk<String> items = new Chunk<>();
 		items.add("foo");
 		items.add("bar");
 
@@ -68,7 +70,7 @@ class Neo4jItemWriterBuilderTests {
 	void testBasicDelete() throws Exception {
 		Neo4jItemWriter<String> writer = new Neo4jItemWriterBuilder<String>().delete(true)
 				.sessionFactory(this.sessionFactory).build();
-		List<String> items = new ArrayList<>();
+		Chunk<String> items = new Chunk<>();
 		items.add("foo");
 		items.add("bar");
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/data/builder/RepositoryItemWriterBuilderTests.java

@@ -24,6 +24,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.data.RepositoryItemWriter;
 import org.springframework.data.repository.CrudRepository;
 
@@ -60,7 +62,7 @@ class RepositoryItemWriterBuilderTests {
 		RepositoryItemWriter<String> writer = new RepositoryItemWriterBuilder<String>().methodName("save")
 				.repository(this.repository).build();
 
-		List<String> items = Collections.singletonList("foo");
+		Chunk<String> items = Chunk.of("foo");
 
 		writer.write(items);
 
@@ -72,7 +74,7 @@ class RepositoryItemWriterBuilderTests {
 		RepositoryItemWriter<String> writer = new RepositoryItemWriterBuilder<String>().methodName("foo")
 				.repository(this.repository).build();
 
-		List<String> items = Collections.singletonList("foo");
+		Chunk<String> items = Chunk.of("foo");
 
 		writer.write(items);
 
@@ -88,7 +90,7 @@ class RepositoryItemWriterBuilderTests {
 		RepositoryItemWriter<String> writer = new RepositoryItemWriterBuilder<String>().methodName("foo")
 				.repository(repositoryMethodReference).build();
 
-		List<String> items = Collections.singletonList("foo");
+		Chunk<String> items = Chunk.of("foo");
 
 		writer.write(items);
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/HibernateItemWriterTests.java

@@ -23,6 +23,8 @@ import org.hibernate.SessionFactory;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -84,7 +86,7 @@ class HibernateItemWriterTests {
 		this.currentSession.flush();
 		this.currentSession.clear();
 
-		List<String> items = Arrays.asList(new String[] { "foo", "bar" });
+		Chunk<String> items = Chunk.of("foo", "bar");
 		writer.write(items);
 
 	}
@@ -95,7 +97,7 @@ class HibernateItemWriterTests {
 		final RuntimeException ex = new RuntimeException("ERROR");
 		when(this.currentSession.contains("foo")).thenThrow(ex);
 
-		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(List.of("foo")));
+		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(Chunk.of("foo")));
 		assertEquals("ERROR", exception.getMessage());
 	}
 
@@ -109,7 +111,7 @@ class HibernateItemWriterTests {
 		currentSession.flush();
 		currentSession.clear();
 
-		List<String> items = Arrays.asList(new String[] { "foo", "bar" });
+		Chunk<String> items = Chunk.of("foo", "bar");
 		writer.write(items);
 	}
 
@@ -121,7 +123,7 @@ class HibernateItemWriterTests {
 		when(factory.getCurrentSession()).thenReturn(currentSession);
 		when(currentSession.contains("foo")).thenThrow(ex);
 
-		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(List.of("foo")));
+		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(Chunk.of("foo")));
 		assertEquals("ERROR", exception.getMessage());
 	}
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/JdbcBatchItemWriterClassicTests.java

@@ -27,6 +27,8 @@ import java.util.List;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.jdbc.UncategorizedSQLException;
@@ -38,6 +40,7 @@ import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
  * @author Dave Syer
  * @author Thomas Risberg
  * @author Will Schipp
+ * @author Mahmoud Ben Hassine
  */
 class JdbcBatchItemWriterClassicTests {
 
@@ -105,7 +108,7 @@ class JdbcBatchItemWriterClassicTests {
 	void testWriteAndFlush() throws Exception {
 		ps.addBatch();
 		when(ps.executeBatch()).thenReturn(new int[] { 123 });
-		writer.write(Collections.singletonList("bar"));
+		writer.write(Chunk.of("bar"));
 		assertEquals(2, list.size());
 		assertTrue(list.contains("SQL"));
 	}
@@ -114,7 +117,7 @@ class JdbcBatchItemWriterClassicTests {
 	void testWriteAndFlushWithEmptyUpdate() throws Exception {
 		ps.addBatch();
 		when(ps.executeBatch()).thenReturn(new int[] { 0 });
-		Exception exception = assertThrows(EmptyResultDataAccessException.class, () -> writer.write(List.of("bar")));
+		Exception exception = assertThrows(EmptyResultDataAccessException.class, () -> writer.write(Chunk.of("bar")));
 		String message = exception.getMessage();
 		assertTrue(message.contains("did not update"), "Wrong message: " + message);
 		assertEquals(2, list.size());
@@ -133,7 +136,7 @@ class JdbcBatchItemWriterClassicTests {
 		});
 		ps.addBatch();
 		when(ps.executeBatch()).thenReturn(new int[] { 123 });
-		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(List.of("foo")));
+		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(Chunk.of("foo")));
 		assertEquals("bar", exception.getMessage());
 		assertEquals(2, list.size());
 		writer.setItemPreparedStatementSetter(new ItemPreparedStatementSetter<String>() {
@@ -142,7 +145,7 @@ class JdbcBatchItemWriterClassicTests {
 				list.add(item);
 			}
 		});
-		writer.write(Collections.singletonList("foo"));
+		writer.write(Chunk.of("foo"));
 		assertEquals(4, list.size());
 		assertTrue(list.contains("SQL"));
 		assertTrue(list.contains("foo"));

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/JdbcBatchItemWriterNamedParameterTests.java

@@ -24,6 +24,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource;
 import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
@@ -43,6 +44,7 @@ import static org.mockito.hamcrest.MockitoHamcrest.argThat;
  * @author Thomas Risberg
  * @author Will Schipp
  * @author Michael Minella
+ * @author Mahmoud Ben Hassine
  */
 public class JdbcBatchItemWriterNamedParameterTests {
 
@@ -119,7 +121,7 @@ public class JdbcBatchItemWriterNamedParameterTests {
 				eqSqlParameterSourceArray(
 						new SqlParameterSource[] { new BeanPropertySqlParameterSource(new Foo("bar")) })))
 				.thenReturn(new int[] { 1 });
-		writer.write(List.of(new Foo("bar")));
+		writer.write(Chunk.of(new Foo("bar")));
 	}
 
 	@SuppressWarnings({ "rawtypes", "unchecked" })
@@ -134,7 +136,7 @@ public class JdbcBatchItemWriterNamedParameterTests {
 		ArgumentCaptor<Map[]> captor = ArgumentCaptor.forClass(Map[].class);
 
 		when(namedParameterJdbcOperations.batchUpdate(eq(sql), captor.capture())).thenReturn(new int[] { 1 });
-		mapWriter.write(List.of(Map.of("foo", "bar")));
+		mapWriter.write(Chunk.of(Map.of("foo", "bar")));
 
 		assertEquals(1, captor.getValue().length);
 		Map<String, Object> results = captor.getValue()[0];
@@ -158,7 +160,7 @@ public class JdbcBatchItemWriterNamedParameterTests {
 		ArgumentCaptor<SqlParameterSource[]> captor = ArgumentCaptor.forClass(SqlParameterSource[].class);
 
 		when(namedParameterJdbcOperations.batchUpdate(any(String.class), captor.capture())).thenReturn(new int[] { 1 });
-		mapWriter.write(List.of(Map.of("foo", "bar")));
+		mapWriter.write(Chunk.of(Map.of("foo", "bar")));
 
 		assertEquals(1, captor.getValue().length);
 		SqlParameterSource results = captor.getValue()[0];
@@ -172,7 +174,7 @@ public class JdbcBatchItemWriterNamedParameterTests {
 						new SqlParameterSource[] { new BeanPropertySqlParameterSource(new Foo("bar")) })))
 				.thenReturn(new int[] { 0 });
 		Exception exception = assertThrows(EmptyResultDataAccessException.class,
-				() -> writer.write(List.of(new Foo("bar"))));
+				() -> writer.write(Chunk.of(new Foo("bar"))));
 		String message = exception.getMessage();
 		assertTrue(message.contains("did not update"), "Wrong message: " + message);
 	}
@@ -184,7 +186,7 @@ public class JdbcBatchItemWriterNamedParameterTests {
 				eqSqlParameterSourceArray(
 						new SqlParameterSource[] { new BeanPropertySqlParameterSource(new Foo("bar")) })))
 				.thenThrow(ex);
-		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(List.of(new Foo("bar"))));
+		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(Chunk.of(new Foo("bar"))));
 		assertEquals("ERROR", exception.getMessage());
 	}
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/JpaItemWriterIntegrationTests.java

@@ -24,6 +24,7 @@ import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.sample.Person;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
@@ -71,7 +72,7 @@ class JpaItemWriterIntegrationTests {
 		JpaItemWriter<Person> writer = new JpaItemWriter<>();
 		writer.setEntityManagerFactory(this.entityManagerFactory);
 		writer.afterPropertiesSet();
-		List<Person> items = Arrays.asList(new Person(1, "foo"), new Person(2, "bar"));
+		Chunk<Person> items = Chunk.of(new Person(1, "foo"), new Person(2, "bar"));
 
 		// when
 		writer.write(items);
@@ -87,7 +88,7 @@ class JpaItemWriterIntegrationTests {
 		writer.setEntityManagerFactory(this.entityManagerFactory);
 		writer.setUsePersist(true);
 		writer.afterPropertiesSet();
-		List<Person> items = Arrays.asList(new Person(1, "foo"), new Person(2, "bar"));
+		Chunk<Person> items = Chunk.of(new Person(1, "foo"), new Person(2, "bar"));
 
 		// when
 		writer.write(items);

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/JpaItemWriterTests.java

@@ -31,6 +31,8 @@ import jakarta.persistence.EntityManagerFactory;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.orm.jpa.EntityManagerHolder;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 
@@ -73,7 +75,7 @@ class JpaItemWriterTests {
 		em.flush();
 		TransactionSynchronizationManager.bindResource(emf, new EntityManagerHolder(em));
 
-		List<String> items = Arrays.asList(new String[] { "foo", "bar" });
+		Chunk<String> items = Chunk.of("foo", "bar");
 
 		writer.write(items);
 
@@ -85,10 +87,10 @@ class JpaItemWriterTests {
 		writer.setUsePersist(true);
 		EntityManager em = mock(EntityManager.class, "em");
 		TransactionSynchronizationManager.bindResource(emf, new EntityManagerHolder(em));
-		List<String> items = Arrays.asList("persist1", "persist2");
-		writer.write(items);
-		verify(em).persist(items.get(0));
-		verify(em).persist(items.get(1));
+		Chunk<String> chunk = Chunk.of("persist1", "persist2");
+		writer.write(chunk);
+		verify(em).persist(chunk.getItems().get(0));
+		verify(em).persist(chunk.getItems().get(1));
 		TransactionSynchronizationManager.unbindResource(emf);
 	}
 
@@ -102,7 +104,7 @@ class JpaItemWriterTests {
 		when(em).thenThrow(ex);
 		TransactionSynchronizationManager.bindResource(emf, new EntityManagerHolder(em));
 
-		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(List.of("foo", "bar")));
+		Exception exception = assertThrows(RuntimeException.class, () -> writer.write(Chunk.of("foo", "bar")));
 		assertEquals("ERROR", exception.getMessage());
 
 		TransactionSynchronizationManager.unbindResource(emf);

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/builder/HibernateItemWriterBuilderTests.java

@@ -25,6 +25,8 @@ import org.junit.jupiter.api.Test;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.database.HibernateItemWriter;
 import org.springframework.batch.item.sample.Foo;
 
@@ -36,6 +38,7 @@ import static org.mockito.Mockito.when;
 
 /**
  * @author Michael Minella
+ * @author Mahmoud Ben Hassine
  */
 @MockitoSettings(strictness = Strictness.LENIENT)
 class HibernateItemWriterBuilderTests {
@@ -58,13 +61,13 @@ class HibernateItemWriterBuilderTests {
 
 		itemWriter.afterPropertiesSet();
 
-		List<Foo> foos = getFoos();
+		Chunk<Foo> foos = getFoos();
 
 		itemWriter.write(foos);
 
-		verify(this.session).saveOrUpdate(foos.get(0));
-		verify(this.session).saveOrUpdate(foos.get(1));
-		verify(this.session).saveOrUpdate(foos.get(2));
+		verify(this.session).saveOrUpdate(foos.getItems().get(0));
+		verify(this.session).saveOrUpdate(foos.getItems().get(1));
+		verify(this.session).saveOrUpdate(foos.getItems().get(2));
 	}
 
 	@Test
@@ -74,13 +77,13 @@ class HibernateItemWriterBuilderTests {
 
 		itemWriter.afterPropertiesSet();
 
-		List<Foo> foos = getFoos();
+		Chunk<Foo> foos = getFoos();
 
 		itemWriter.write(foos);
 
-		verify(this.session).saveOrUpdate(foos.get(0));
-		verify(this.session).saveOrUpdate(foos.get(1));
-		verify(this.session).saveOrUpdate(foos.get(2));
+		verify(this.session).saveOrUpdate(foos.getItems().get(0));
+		verify(this.session).saveOrUpdate(foos.getItems().get(1));
+		verify(this.session).saveOrUpdate(foos.getItems().get(2));
 		verify(this.session, never()).clear();
 	}
 
@@ -91,8 +94,8 @@ class HibernateItemWriterBuilderTests {
 		assertEquals("SessionFactory must be provided", exception.getMessage());
 	}
 
-	private List<Foo> getFoos() {
-		List<Foo> foos = new ArrayList<>(3);
+	private Chunk<Foo> getFoos() {
+		Chunk<Foo> foos = new Chunk<>();
 
 		for (int i = 1; i < 4; i++) {
 			Foo foo = new Foo();

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/builder/JdbcBatchItemWriterBuilderTests.java

@@ -25,6 +25,7 @@ import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.database.JdbcBatchItemWriter;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
@@ -49,6 +50,7 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * @author Michael Minella
+ * @author Mahmoud Ben Hassine
  */
 class JdbcBatchItemWriterBuilderTests {
 
@@ -77,8 +79,8 @@ class JdbcBatchItemWriterBuilderTests {
 
 		writer.afterPropertiesSet();
 
-		List<Map<String, Object>> items = buildMapItems();
-		writer.write(items);
+		Chunk<Map<String, Object>> chunk = buildMapItems();
+		writer.write(chunk);
 
 		verifyWrite();
 	}
@@ -93,7 +95,7 @@ class JdbcBatchItemWriterBuilderTests {
 
 		writer.afterPropertiesSet();
 
-		List<Map<String, Object>> items = buildMapItems();
+		Chunk<Map<String, Object>> items = buildMapItems();
 		writer.write(items);
 
 		verifyWrite();
@@ -109,7 +111,7 @@ class JdbcBatchItemWriterBuilderTests {
 
 		writer.afterPropertiesSet();
 
-		List<Foo> items = new ArrayList<>(3);
+		Chunk<Foo> items = new Chunk<>();
 
 		items.add(new Foo(1, "two", "three"));
 		items.add(new Foo(4, "five", "six"));
@@ -128,7 +130,7 @@ class JdbcBatchItemWriterBuilderTests {
 
 		writer.afterPropertiesSet();
 
-		List<Foo> items = new ArrayList<>(1);
+		Chunk<Foo> items = new Chunk<>();
 
 		items.add(new Foo(1, "two", "three"));
 
@@ -147,7 +149,7 @@ class JdbcBatchItemWriterBuilderTests {
 
 		writer.afterPropertiesSet();
 
-		List<Map<String, Object>> items = buildMapItems();
+		Chunk<Map<String, Object>> items = buildMapItems();
 		writer.write(items);
 
 		verifyWrite();
@@ -161,7 +163,7 @@ class JdbcBatchItemWriterBuilderTests {
 
 		writer.afterPropertiesSet();
 
-		List<Map<String, Object>> items = buildMapItems();
+		Chunk<Map<String, Object>> items = buildMapItems();
 		writer.write(items);
 
 		verifyWrite();
@@ -192,8 +194,8 @@ class JdbcBatchItemWriterBuilderTests {
 		verifyRow(7, "eight", "nine");
 	}
 
-	private List<Map<String, Object>> buildMapItems() {
-		List<Map<String, Object>> items = new ArrayList<>(3);
+	private Chunk<Map<String, Object>> buildMapItems() {
+		Chunk<Map<String, Object>> items = new Chunk<>();
 
 		Map<String, Object> item = new HashMap<>(3);
 		item.put("first", 1);

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/database/builder/JpaItemWriterBuilderTests.java

@@ -26,6 +26,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.database.JpaItemWriter;
 import org.springframework.orm.jpa.EntityManagerHolder;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
@@ -64,12 +66,12 @@ class JpaItemWriterBuilderTests {
 
 		itemWriter.afterPropertiesSet();
 
-		List<String> items = Arrays.asList("foo", "bar");
+		Chunk<String> chunk = Chunk.of("foo", "bar");
 
-		itemWriter.write(items);
+		itemWriter.write(chunk);
 
-		verify(this.entityManager).merge(items.get(0));
-		verify(this.entityManager).merge(items.get(1));
+		verify(this.entityManager).merge(chunk.getItems().get(0));
+		verify(this.entityManager).merge(chunk.getItems().get(1));
 	}
 
 	@Test
@@ -86,12 +88,12 @@ class JpaItemWriterBuilderTests {
 
 		itemWriter.afterPropertiesSet();
 
-		List<String> items = Arrays.asList("foo", "bar");
+		Chunk<String> chunk = Chunk.of("foo", "bar");
 
-		itemWriter.write(items);
+		itemWriter.write(chunk);
 
-		verify(this.entityManager).persist(items.get(0));
-		verify(this.entityManager).persist(items.get(1));
+		verify(this.entityManager).persist(chunk.getItems().get(0));
+		verify(this.entityManager).persist(chunk.getItems().get(1));
 	}
 
 }

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/FlatFileItemWriterTests.java

@@ -32,6 +32,7 @@ import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.batch.item.UnexpectedInputException;
@@ -60,6 +61,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
  *
  * @author Robert Kasanicky
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  *
  */
 class FlatFileItemWriterTests {
@@ -145,9 +147,9 @@ class FlatFileItemWriterTests {
 	@Test
 	void testWriteWithMultipleOpen() throws Exception {
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test1"));
+		writer.write(Chunk.of("test1"));
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test2"));
+		writer.write(Chunk.of("test2"));
 		assertEquals("test1", readLine());
 		assertEquals("test2", readLine());
 	}
@@ -155,13 +157,13 @@ class FlatFileItemWriterTests {
 	@Test
 	void testWriteWithDelete() throws Exception {
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test1"));
+		writer.write(Chunk.of("test1"));
 		writer.close();
 		assertEquals("test1", readLine());
 		closeReader();
 		writer.setShouldDeleteIfExists(true);
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test2"));
+		writer.write(Chunk.of("test2"));
 		assertEquals("test2", readLine());
 	}
 
@@ -169,12 +171,12 @@ class FlatFileItemWriterTests {
 	void testWriteWithAppend() throws Exception {
 		writer.setAppendAllowed(true);
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test1"));
+		writer.write(Chunk.of("test1"));
 		writer.close();
 		assertEquals("test1", readLine());
 		closeReader();
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test2"));
+		writer.write(Chunk.of("test2"));
 		assertEquals("test1", readLine());
 		assertEquals("test2", readLine());
 	}
@@ -185,21 +187,21 @@ class FlatFileItemWriterTests {
 		writer.setShouldDeleteIfExists(true);
 		writer.setAppendAllowed(true);
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test1"));
+		writer.write(Chunk.of("test1"));
 		writer.close();
 		assertEquals("test1", readLine());
 		closeReader();
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.update(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		assertEquals("test1", readLine());
 		assertEquals(TEST_STRING, readLine());
 		assertEquals(TEST_STRING, readLine());
 		assertNull(readLine());
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		closeReader();
 		assertEquals("test1", readLine());
@@ -222,7 +224,7 @@ class FlatFileItemWriterTests {
 	@Test
 	void testWriteString() throws Exception {
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		String lineFromFile = readLine();
 
@@ -233,7 +235,7 @@ class FlatFileItemWriterTests {
 	void testForcedWriteString() throws Exception {
 		writer.setForceSync(true);
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		String lineFromFile = readLine();
 
@@ -254,7 +256,7 @@ class FlatFileItemWriterTests {
 		});
 		String data = "string";
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(data));
+		writer.write(Chunk.of(data));
 		String lineFromFile = readLine();
 		// converter not used if input is String
 		assertEquals("FOO:" + data, lineFromFile);
@@ -273,7 +275,7 @@ class FlatFileItemWriterTests {
 			}
 		});
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		String lineFromFile = readLine();
 		assertEquals("FOO:" + TEST_STRING, lineFromFile);
 	}
@@ -285,7 +287,7 @@ class FlatFileItemWriterTests {
 	@Test
 	void testWriteRecord() throws Exception {
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("1"));
+		writer.write(Chunk.of("1"));
 		String lineFromFile = readLine();
 		assertEquals("1", lineFromFile);
 	}
@@ -294,7 +296,7 @@ class FlatFileItemWriterTests {
 	void testWriteRecordWithrecordSeparator() throws Exception {
 		writer.setLineSeparator("|");
 		writer.open(executionContext);
-		writer.write(Arrays.asList(new String[] { "1", "2" }));
+		writer.write(Chunk.of(new String[] { "1", "2" }));
 		String lineFromFile = readLine();
 		assertEquals("1|2|", lineFromFile);
 	}
@@ -313,9 +315,9 @@ class FlatFileItemWriterTests {
 
 		writer.open(executionContext);
 		// write some lines
-		writer.write(Arrays.asList(new String[] { "testLine1", "testLine2", "testLine3" }));
+		writer.write(Chunk.of(new String[] { "testLine1", "testLine2", "testLine3" }));
 		// write more lines
-		writer.write(Arrays.asList(new String[] { "testLine4", "testLine5" }));
+		writer.write(Chunk.of(new String[] { "testLine4", "testLine5" }));
 		// get restart data
 		writer.update(executionContext);
 		// close template
@@ -324,7 +326,7 @@ class FlatFileItemWriterTests {
 		// init with correct data
 		writer.open(executionContext);
 		// write more lines
-		writer.write(Arrays.asList(new String[] { "testLine6", "testLine7", "testLine8" }));
+		writer.write(Chunk.of(new String[] { "testLine6", "testLine7", "testLine8" }));
 		// get statistics
 		writer.update(executionContext);
 		// close template
@@ -362,7 +364,7 @@ class FlatFileItemWriterTests {
 			@Override
 			public Void doInTransaction(TransactionStatus status) {
 				try {
-					writer.write(Collections.singletonList(TEST_STRING));
+					writer.write(Chunk.of(TEST_STRING));
 					assertEquals(expectedInTransaction, readLine());
 				}
 				catch (Exception e) {
@@ -396,9 +398,9 @@ class FlatFileItemWriterTests {
 			public Void doInTransaction(TransactionStatus status) {
 				try {
 					// write some lines
-					writer.write(Arrays.asList(new String[] { "testLine1", "testLine2", "testLine3" }));
+					writer.write(Chunk.of(new String[] { "testLine1", "testLine2", "testLine3" }));
 					// write more lines
-					writer.write(Arrays.asList(new String[] { "testLine4", "testLine5" }));
+					writer.write(Chunk.of(new String[] { "testLine4", "testLine5" }));
 				}
 				catch (Exception e) {
 					throw new UnexpectedInputException("Could not write data", e);
@@ -419,7 +421,7 @@ class FlatFileItemWriterTests {
 			public Void doInTransaction(TransactionStatus status) {
 				try {
 					// write more lines
-					writer.write(Arrays.asList(new String[] { "testLine6", "testLine7", "testLine8" }));
+					writer.write(Chunk.of(new String[] { "testLine6", "testLine7", "testLine8" }));
 				}
 				catch (Exception e) {
 					throw new UnexpectedInputException("Could not write data", e);
@@ -476,9 +478,9 @@ class FlatFileItemWriterTests {
 			public Void doInTransaction(TransactionStatus status) {
 				try {
 					// write some lines
-					writer.write(Arrays.asList(new String[] { "téstLine1", "téstLine2", "téstLine3" }));
+					writer.write(Chunk.of(new String[] { "téstLine1", "téstLine2", "téstLine3" }));
 					// write more lines
-					writer.write(Arrays.asList(new String[] { "téstLine4", "téstLine5" }));
+					writer.write(Chunk.of(new String[] { "téstLine4", "téstLine5" }));
 				}
 				catch (Exception e) {
 					throw new UnexpectedInputException("Could not write data", e);
@@ -499,7 +501,7 @@ class FlatFileItemWriterTests {
 			public Void doInTransaction(TransactionStatus status) {
 				try {
 					// write more lines
-					writer.write(Arrays.asList(new String[] { "téstLine6", "téstLine7", "téstLine8" }));
+					writer.write(Chunk.of(new String[] { "téstLine6", "téstLine7", "téstLine8" }));
 				}
 				catch (Exception e) {
 					throw new UnexpectedInputException("Could not write data", e);
@@ -571,17 +573,17 @@ class FlatFileItemWriterTests {
 		// Try and write after the exception on open:
 		writer.setEncoding("UTF-8");
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 	}
 
 	@Test
 	void testWriteStringWithEncodingAfterClose() throws Exception {
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		writer.setEncoding("UTF-8");
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		String lineFromFile = readLine();
 
 		assertEquals(TEST_STRING, lineFromFile);
@@ -598,7 +600,7 @@ class FlatFileItemWriterTests {
 
 		});
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		assertEquals(TEST_STRING, readLine());
 		assertEquals("a", readLine());
@@ -616,7 +618,7 @@ class FlatFileItemWriterTests {
 
 		});
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		String lineFromFile = readLine();
 		assertEquals("a", lineFromFile);
@@ -637,14 +639,14 @@ class FlatFileItemWriterTests {
 		});
 		writer.setAppendAllowed(true);
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test1"));
+		writer.write(Chunk.of("test1"));
 		writer.close();
 		assertEquals("a", readLine());
 		assertEquals("b", readLine());
 		assertEquals("test1", readLine());
 		closeReader();
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test2"));
+		writer.write(Chunk.of("test2"));
 		assertEquals("a", readLine());
 		assertEquals("b", readLine());
 		assertEquals("test1", readLine());
@@ -677,7 +679,7 @@ class FlatFileItemWriterTests {
 		writer.close();
 		assertFalse(outputFile.exists());
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test2"));
+		writer.write(Chunk.of("test2"));
 		assertEquals("test2", readLine());
 	}
 
@@ -699,7 +701,7 @@ class FlatFileItemWriterTests {
 		assertFalse(outputFile.exists());
 
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test2"));
+		writer.write(Chunk.of("test2"));
 		assertEquals("a", readLine());
 		assertEquals("b", readLine());
 		assertEquals("test2", readLine());
@@ -709,7 +711,7 @@ class FlatFileItemWriterTests {
 	void testDeleteOnExitNoRecordsWrittenAfterRestart() throws Exception {
 		writer.setShouldDeleteIfEmpty(true);
 		writer.open(executionContext);
-		writer.write(Collections.singletonList("test2"));
+		writer.write(Chunk.of("test2"));
 		writer.update(executionContext);
 		writer.close();
 		assertTrue(outputFile.exists());
@@ -729,10 +731,10 @@ class FlatFileItemWriterTests {
 
 		});
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		String lineFromFile = readLine();
 		assertEquals("a", lineFromFile);
@@ -755,9 +757,9 @@ class FlatFileItemWriterTests {
 
 		});
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.update(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		String lineFromFile = readLine();
 		assertEquals("a", lineFromFile);
@@ -766,7 +768,7 @@ class FlatFileItemWriterTests {
 		lineFromFile = readLine();
 		assertEquals(TEST_STRING, lineFromFile);
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(TEST_STRING));
+		writer.write(Chunk.of(TEST_STRING));
 		writer.close();
 		closeReader();
 		lineFromFile = readLine();
@@ -795,13 +797,7 @@ class FlatFileItemWriterTests {
 				return item;
 			}
 		});
-		List<String> items = new ArrayList<String>() {
-			{
-				add("1");
-				add("2");
-				add("3");
-			}
-		};
+		Chunk<String> items = Chunk.of("1", "2", "3");
 
 		writer.open(executionContext);
 		Exception expected = assertThrows(RuntimeException.class, () -> writer.write(items));
@@ -830,7 +826,7 @@ class FlatFileItemWriterTests {
 		writer.open(executionContext);
 		assertTrue(toBeCreated.exists(), "output file was created");
 
-		writer.write(Collections.singletonList("test1"));
+		writer.write(Chunk.of("test1"));
 		writer.close();
 		assertEquals("test1", readLine());
 	}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/MultiResourceItemWriterFlatFileTests.java

@@ -26,6 +26,8 @@ import java.util.List;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.file.transform.PassThroughLineAggregator;
 import org.springframework.batch.support.transaction.ResourcelessTransactionManager;
 import org.springframework.transaction.TransactionStatus;
@@ -43,9 +45,9 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 	 */
 	private final class WriterCallback implements TransactionCallback<Void> {
 
-		private List<? extends String> list;
+		private Chunk<? extends String> list;
 
-		public WriterCallback(List<? extends String> list) {
+		public WriterCallback(Chunk<? extends String> list) {
 			super();
 			this.list = list;
 		}
@@ -78,21 +80,21 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 		super.setUp(delegate);
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("1", "2", "3"));
+		tested.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123", readFile(part1));
 
-		tested.write(Arrays.asList("4"));
+		tested.write(Chunk.of("4"));
 		File part2 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
 
-		tested.write(Arrays.asList("5"));
+		tested.write(Chunk.of("5"));
 		assertEquals("45", readFile(part2));
 
-		tested.write(Arrays.asList("6", "7", "8", "9"));
+		tested.write(Chunk.of("6", "7", "8", "9"));
 		File part3 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(3));
 		assertTrue(part3.exists());
 		assertEquals("6789", readFile(part3));
@@ -107,7 +109,7 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 		tested.update(executionContext);
 		assertEquals(0, executionContext.getInt(tested.getExecutionContextKey("resource.item.count")));
 		assertEquals(1, executionContext.getInt(tested.getExecutionContextKey("resource.index")));
-		tested.write(Arrays.asList("1", "2", "3"));
+		tested.write(Chunk.of("1", "2", "3"));
 		tested.update(executionContext);
 		assertEquals(0, executionContext.getInt(tested.getExecutionContextKey("resource.item.count")));
 		assertEquals(2, executionContext.getInt(tested.getExecutionContextKey("resource.index")));
@@ -126,12 +128,12 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 		super.setUp(delegate);
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("1", "2", "3"));
+		tested.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 
-		tested.write(Arrays.asList("4"));
+		tested.write(Chunk.of("4"));
 		File part2 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 
@@ -156,12 +158,12 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 
 		ResourcelessTransactionManager transactionManager = new ResourcelessTransactionManager();
 
-		new TransactionTemplate(transactionManager).execute(new WriterCallback(Arrays.asList("1", "2", "3")));
+		new TransactionTemplate(transactionManager).execute(new WriterCallback(Chunk.of("1", "2", "3")));
 
 		File part1 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 
-		new TransactionTemplate(transactionManager).execute(new WriterCallback(Arrays.asList("4")));
+		new TransactionTemplate(transactionManager).execute(new WriterCallback(Chunk.of("4")));
 		File part2 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 
@@ -178,13 +180,13 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 		super.setUp(delegate);
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("1", "2", "3"));
+		tested.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123", readFile(part1));
 
-		tested.write(Arrays.asList("4"));
+		tested.write(Chunk.of("4"));
 		File part2 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
@@ -194,10 +196,10 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("5"));
+		tested.write(Chunk.of("5"));
 		assertEquals("45", readFile(part2));
 
-		tested.write(Arrays.asList("6", "7", "8", "9"));
+		tested.write(Chunk.of("6", "7", "8", "9"));
 		File part3 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(3));
 		assertTrue(part3.exists());
 		assertEquals("6789", readFile(part3));
@@ -216,13 +218,13 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 		super.setUp(delegate);
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("1", "2", "3"));
+		tested.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123f", readFile(part1));
 
-		tested.write(Arrays.asList("4"));
+		tested.write(Chunk.of("4"));
 		File part2 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
@@ -232,10 +234,10 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("5"));
+		tested.write(Chunk.of("5"));
 		assertEquals("45f", readFile(part2));
 
-		tested.write(Arrays.asList("6", "7", "8", "9"));
+		tested.write(Chunk.of("6", "7", "8", "9"));
 		File part3 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(3));
 		assertTrue(part3.exists());
 		assertEquals("6789f", readFile(part3));
@@ -255,13 +257,13 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 
 		ResourcelessTransactionManager transactionManager = new ResourcelessTransactionManager();
 
-		new TransactionTemplate(transactionManager).execute(new WriterCallback(Arrays.asList("1", "2", "3")));
+		new TransactionTemplate(transactionManager).execute(new WriterCallback(Chunk.of("1", "2", "3")));
 
 		File part1 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123f", readFile(part1));
 
-		new TransactionTemplate(transactionManager).execute(new WriterCallback(Arrays.asList("4")));
+		new TransactionTemplate(transactionManager).execute(new WriterCallback(Chunk.of("4")));
 		File part2 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
@@ -271,7 +273,7 @@ public class MultiResourceItemWriterFlatFileTests extends AbstractMultiResourceI
 
 		tested.open(executionContext);
 
-		new TransactionTemplate(transactionManager).execute(new WriterCallback(Arrays.asList("5")));
+		new TransactionTemplate(transactionManager).execute(new WriterCallback(Chunk.of("5")));
 		assertEquals("45f", readFile(part2));
 	}
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/MultiResourceItemWriterXmlTests.java

@@ -28,6 +28,8 @@ import javax.xml.transform.Result;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.xml.StaxEventItemWriter;
 import org.springframework.batch.item.xml.StaxTestUtils;
 import org.springframework.oxm.Marshaller;
@@ -95,12 +97,12 @@ class MultiResourceItemWriterXmlTests extends AbstractMultiResourceItemWriterTes
 		super.setUp(delegate);
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("1", "2", "3"));
+		tested.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 
-		tested.write(Arrays.asList("4"));
+		tested.write(Chunk.of("4"));
 		File part2 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 
@@ -112,9 +114,9 @@ class MultiResourceItemWriterXmlTests extends AbstractMultiResourceItemWriterTes
 
 		tested.open(executionContext);
 
-		tested.write(Arrays.asList("5"));
+		tested.write(Chunk.of("5"));
 
-		tested.write(Arrays.asList("6", "7", "8", "9"));
+		tested.write(Chunk.of("6", "7", "8", "9"));
 		File part3 = new File(file.getAbsolutePath() + suffixCreator.getSuffix(3));
 		assertTrue(part3.exists());
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilderTests.java

@@ -24,6 +24,7 @@ import java.util.Arrays;
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.file.FlatFileItemWriter;
 import org.springframework.batch.item.file.transform.BeanWrapperFieldExtractor;
@@ -83,7 +84,7 @@ class FlatFileItemWriterBuilderTests {
 
 		writer.open(executionContext);
 
-		writer.write(Arrays.asList(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
 
 		writer.close();
 
@@ -105,7 +106,7 @@ class FlatFileItemWriterBuilderTests {
 
 		writer.open(executionContext);
 
-		writer.write(Arrays.asList(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
 
 		writer.close();
 
@@ -126,7 +127,7 @@ class FlatFileItemWriterBuilderTests {
 
 		writer.open(executionContext);
 
-		writer.write(Arrays.asList(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
 
 		writer.close();
 
@@ -147,7 +148,7 @@ class FlatFileItemWriterBuilderTests {
 
 		writer.open(executionContext);
 
-		writer.write(Arrays.asList(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
 
 		writer.close();
 
@@ -169,7 +170,7 @@ class FlatFileItemWriterBuilderTests {
 
 		writer.open(executionContext);
 
-		writer.write(Arrays.asList(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
 
 		writer.close();
 
@@ -190,7 +191,7 @@ class FlatFileItemWriterBuilderTests {
 
 		writer.open(executionContext);
 
-		writer.write(Arrays.asList(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
 
 		writer.close();
 
@@ -212,7 +213,7 @@ class FlatFileItemWriterBuilderTests {
 
 		writer.open(executionContext);
 
-		writer.write(Arrays.asList(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
 
 		writer.close();
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/MultiResourceItemWriterBuilderTests.java

@@ -25,6 +25,7 @@ import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.file.FlatFileItemWriter;
 import org.springframework.batch.item.file.MultiResourceItemWriter;
@@ -40,6 +41,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  */
 class MultiResourceItemWriterBuilderTests {
 
@@ -82,21 +84,21 @@ class MultiResourceItemWriterBuilderTests {
 
 		this.writer.open(this.executionContext);
 
-		this.writer.write(Arrays.asList("1", "2", "3"));
+		this.writer.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123", readFile(part1));
 
-		this.writer.write(Arrays.asList("4"));
+		this.writer.write(Chunk.of("4"));
 		File part2 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
 
-		this.writer.write(Arrays.asList("5"));
+		this.writer.write(Chunk.of("5"));
 		assertEquals("45", readFile(part2));
 
-		this.writer.write(Arrays.asList("6", "7", "8", "9"));
+		this.writer.write(Chunk.of("6", "7", "8", "9"));
 		File part3 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(3));
 		assertTrue(part3.exists());
 		assertEquals("6789", readFile(part3));
@@ -112,13 +114,13 @@ class MultiResourceItemWriterBuilderTests {
 
 		this.writer.open(this.executionContext);
 
-		this.writer.write(Arrays.asList("1", "2", "3"));
+		this.writer.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(this.file.getAbsolutePath() + simpleResourceSuffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123", readFile(part1));
 
-		this.writer.write(Arrays.asList("4"));
+		this.writer.write(Chunk.of("4"));
 		File part2 = new File(this.file.getAbsolutePath() + simpleResourceSuffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
@@ -134,7 +136,7 @@ class MultiResourceItemWriterBuilderTests {
 		this.writer.update(this.executionContext);
 		assertEquals(0, this.executionContext.getInt(this.writer.getExecutionContextKey("resource.item.count")));
 		assertEquals(1, this.executionContext.getInt(this.writer.getExecutionContextKey("resource.index")));
-		this.writer.write(Arrays.asList("1", "2", "3"));
+		this.writer.write(Chunk.of("1", "2", "3"));
 		this.writer.update(this.executionContext);
 		assertEquals(0, this.executionContext.getInt(this.writer.getExecutionContextKey("resource.item.count")));
 		assertEquals(2, this.executionContext.getInt(this.writer.getExecutionContextKey("resource.index")));
@@ -147,13 +149,13 @@ class MultiResourceItemWriterBuilderTests {
 				.resource(new FileSystemResource(this.file)).resourceSuffixCreator(this.suffixCreator)
 				.itemCountLimitPerResource(2).saveState(true).name("foo").build();
 
-		this.writer.write(Arrays.asList("1", "2", "3"));
+		this.writer.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123", readFile(part1));
 
-		this.writer.write(Arrays.asList("4"));
+		this.writer.write(Chunk.of("4"));
 		File part2 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
@@ -162,10 +164,10 @@ class MultiResourceItemWriterBuilderTests {
 		this.writer.close();
 		this.writer.open(this.executionContext);
 
-		this.writer.write(Arrays.asList("5"));
+		this.writer.write(Chunk.of("5"));
 		assertEquals("45", readFile(part2));
 
-		this.writer.write(Arrays.asList("6", "7", "8", "9"));
+		this.writer.write(Chunk.of("6", "7", "8", "9"));
 		File part3 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(3));
 		assertTrue(part3.exists());
 		assertEquals("6789", readFile(part3));
@@ -178,13 +180,13 @@ class MultiResourceItemWriterBuilderTests {
 				.resource(new FileSystemResource(this.file)).resourceSuffixCreator(this.suffixCreator)
 				.itemCountLimitPerResource(2).saveState(false).name("foo").build();
 
-		this.writer.write(Arrays.asList("1", "2", "3"));
+		this.writer.write(Chunk.of("1", "2", "3"));
 
 		File part1 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(1));
 		assertTrue(part1.exists());
 		assertEquals("123", readFile(part1));
 
-		this.writer.write(Arrays.asList("4"));
+		this.writer.write(Chunk.of("4"));
 		File part2 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(2));
 		assertTrue(part2.exists());
 		assertEquals("4", readFile(part2));
@@ -193,10 +195,10 @@ class MultiResourceItemWriterBuilderTests {
 		this.writer.close();
 		this.writer.open(this.executionContext);
 
-		this.writer.write(Arrays.asList("5"));
+		this.writer.write(Chunk.of("5"));
 		assertEquals("4", readFile(part2));
 
-		this.writer.write(Arrays.asList("6", "7", "8", "9"));
+		this.writer.write(Chunk.of("6", "7", "8", "9"));
 		File part3 = new File(this.file.getAbsolutePath() + this.suffixCreator.getSuffix(1));
 		assertTrue(part3.exists());
 		assertEquals("56789", readFile(part3));

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/jms/JmsItemWriterTests.java

@@ -22,6 +22,8 @@ import static org.mockito.Mockito.mock;
 import java.util.Arrays;
 
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.jms.core.JmsOperations;
 import org.springframework.jms.core.JmsTemplate;
 
@@ -36,7 +38,7 @@ class JmsItemWriterTests {
 		jmsTemplate.convertAndSend("bar");
 
 		itemWriter.setJmsTemplate(jmsTemplate);
-		itemWriter.write(Arrays.asList("foo", "bar"));
+		itemWriter.write(Chunk.of("foo", "bar"));
 	}
 
 	@Test

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/jms/builder/JmsItemWriterBuilderTests.java

@@ -21,6 +21,7 @@ import java.util.Arrays;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.jms.JmsItemWriter;
 import org.springframework.jms.core.JmsOperations;
 
@@ -41,7 +42,7 @@ class JmsItemWriterBuilderTests {
 		JmsOperations jmsTemplate = mock(JmsOperations.class);
 		JmsItemWriter<String> itemWriter = new JmsItemWriterBuilder<String>().jmsTemplate(jmsTemplate).build();
 		ArgumentCaptor<String> argCaptor = ArgumentCaptor.forClass(String.class);
-		itemWriter.write(Arrays.asList("foo", "bar"));
+		itemWriter.write(Chunk.of("foo", "bar"));
 		verify(jmsTemplate, times(2)).convertAndSend(argCaptor.capture());
 		assertEquals("foo", argCaptor.getAllValues().get(0), "Expected foo");
 		assertEquals("bar", argCaptor.getAllValues().get(1), "Expected bar");

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/json/JsonFileItemWriterFunctionalTests.java

@@ -30,6 +30,7 @@ import java.util.List;
 import org.junit.jupiter.api.Test;
 import org.skyscreamer.jsonassert.JSONAssert;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.UnexpectedInputException;
 import org.springframework.batch.item.json.builder.JsonFileItemWriterBuilder;
@@ -76,7 +77,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(new ExecutionContext());
-		writer.write(Arrays.asList(this.trade1, this.trade2));
+		writer.write(Chunk.of(this.trade1, this.trade2));
 		writer.close();
 
 		// then
@@ -93,8 +94,8 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(new ExecutionContext());
-		writer.write(Arrays.asList(this.trade1, this.trade2));
-		writer.write(Arrays.asList(this.trade3, this.trade4));
+		writer.write(Chunk.of(this.trade1, this.trade2));
+		writer.write(Chunk.of(this.trade3, this.trade4));
 		writer.close();
 
 		// then
@@ -112,7 +113,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(new ExecutionContext());
-		writer.write(Arrays.asList(this.trade1, this.trade2));
+		writer.write(Chunk.of(this.trade1, this.trade2));
 		writer.close();
 
 		// when
@@ -133,7 +134,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(new ExecutionContext());
-		writer.write(Arrays.asList(this.trade1, this.trade2));
+		writer.write(Chunk.of(this.trade1, this.trade2));
 		writer.close();
 
 		// then
@@ -151,7 +152,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(new ExecutionContext());
-		writer.write(Collections.singletonList(this.trade1));
+		writer.write(Chunk.of(this.trade1));
 		writer.close();
 
 		// then
@@ -169,10 +170,10 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(this.trade1));
+		writer.write(Chunk.of(this.trade1));
 		writer.close();
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(this.trade2));
+		writer.write(Chunk.of(this.trade2));
 		writer.close();
 
 		// then
@@ -191,7 +192,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 		// when
 		writer.open(executionContext);
 		// write some lines
-		writer.write(Collections.singletonList(this.trade1));
+		writer.write(Chunk.of(this.trade1));
 		// get restart data
 		writer.update(executionContext);
 		// close template
@@ -200,7 +201,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 		// init with correct data
 		writer.open(executionContext);
 		// write more lines
-		writer.write(Collections.singletonList(this.trade2));
+		writer.write(Chunk.of(this.trade2));
 		// get statistics
 		writer.update(executionContext);
 		// close template
@@ -229,7 +230,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 		new TransactionTemplate(transactionManager).execute((TransactionCallback<Void>) status -> {
 			try {
 				// write some lines
-				writer.write(Collections.singletonList(this.trade1));
+				writer.write(Chunk.of(this.trade1));
 			}
 			catch (Exception e) {
 				throw new UnexpectedInputException("Could not write data", e);
@@ -247,7 +248,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 		new TransactionTemplate(transactionManager).execute((TransactionCallback<Void>) status -> {
 			try {
 				// write more lines
-				writer.write(Collections.singletonList(this.trade2));
+				writer.write(Chunk.of(this.trade2));
 			}
 			catch (Exception e) {
 				throw new UnexpectedInputException("Could not write data", e);
@@ -279,7 +280,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(executionContext);
-		Exception exception = assertThrows(IllegalArgumentException.class, () -> writer.write(List.of(this.trade1)));
+		Exception exception = assertThrows(IllegalArgumentException.class, () -> writer.write(Chunk.of(this.trade1)));
 		assertEquals("Bad item", exception.getMessage());
 
 		writer.close();
@@ -303,7 +304,7 @@ abstract class JsonFileItemWriterFunctionalTests {
 
 		// when
 		writer.open(executionContext);
-		writer.write(Collections.singletonList(this.trade1));
+		writer.write(Chunk.of(this.trade1));
 		writer.close();
 
 		// then

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/json/JsonFileItemWriterTests.java

@@ -27,6 +27,7 @@ import org.mockito.Mock;
 import org.mockito.Mockito;
 import org.mockito.junit.jupiter.MockitoExtension;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.core.io.FileSystemResource;
 import org.springframework.core.io.WritableResource;
@@ -67,7 +68,7 @@ class JsonFileItemWriterTests {
 
 		// when
 		writer.open(new ExecutionContext());
-		writer.write(Arrays.asList("foo", "bar"));
+		writer.write(Chunk.of("foo", "bar"));
 		writer.close();
 
 		// then

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/kafka/KafkaItemWriterTests.java

@@ -25,6 +25,8 @@ import org.junit.jupiter.api.Test;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.kafka.core.KafkaTemplate;
 import org.springframework.kafka.support.SendResult;
@@ -80,10 +82,11 @@ class KafkaItemWriterTests {
 
 	@Test
 	void testBasicWrite() throws Exception {
-		List<String> items = Arrays.asList("val1", "val2");
+		Chunk<String> chunk = Chunk.of("val1", "val2");
 
-		this.writer.write(items);
+		this.writer.write(chunk);
 
+		List<String> items = chunk.getItems();
 		verify(this.kafkaTemplate).sendDefault(items.get(0), items.get(0));
 		verify(this.kafkaTemplate).sendDefault(items.get(1), items.get(1));
 		verify(this.kafkaTemplate).flush();
@@ -92,11 +95,12 @@ class KafkaItemWriterTests {
 
 	@Test
 	void testBasicDelete() throws Exception {
-		List<String> items = Arrays.asList("val1", "val2");
+		Chunk<String> chunk = Chunk.of("val1", "val2");
 		this.writer.setDelete(true);
 
-		this.writer.write(items);
+		this.writer.write(chunk);
 
+		List<String> items = chunk.getItems();
 		verify(this.kafkaTemplate).sendDefault(items.get(0), null);
 		verify(this.kafkaTemplate).sendDefault(items.get(1), null);
 		verify(this.kafkaTemplate).flush();

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/mail/SimpleMailMessageItemWriterTests.java

@@ -32,6 +32,7 @@ import jakarta.mail.MessagingException;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.mail.MailException;
 import org.springframework.mail.MailMessage;
 import org.springframework.mail.MailSendException;
@@ -64,7 +65,7 @@ class SimpleMailMessageItemWriterTests {
 		SimpleMailMessage bar = new SimpleMailMessage();
 		SimpleMailMessage[] items = new SimpleMailMessage[] { foo, bar };
 
-		writer.write(Arrays.asList(items));
+		writer.write(Chunk.of(items));
 
 		// Spring 4.1 changed the send method to be vargs instead of an array
 		if (ReflectionUtils.findMethod(SimpleMailMessage.class, "send", SimpleMailMessage[].class) != null) {
@@ -93,7 +94,7 @@ class SimpleMailMessageItemWriterTests {
 		when(mailSender).thenThrow(new MailSendException(
 				Collections.singletonMap((Object) foo, (Exception) new MessagingException("FOO"))));
 
-		assertThrows(MailSendException.class, () -> writer.write(List.of(items)));
+		assertThrows(MailSendException.class, () -> writer.write(Chunk.of(items)));
 	}
 
 	@Test
@@ -122,7 +123,7 @@ class SimpleMailMessageItemWriterTests {
 		when(mailSender).thenThrow(new MailSendException(
 				Collections.singletonMap((Object) foo, (Exception) new MessagingException("FOO"))));
 
-		writer.write(Arrays.asList(items));
+		writer.write(Chunk.of(items));
 
 		assertEquals("FOO", content.get());
 	}

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/mail/builder/SimpleMailMessageItemWriterBuilderTests.java

@@ -26,6 +26,7 @@ import jakarta.mail.MessagingException;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.mail.MailErrorHandler;
 import org.springframework.batch.item.mail.SimpleMailMessageItemWriter;
 import org.springframework.mail.MailException;
@@ -67,7 +68,7 @@ class SimpleMailMessageItemWriterBuilderTests {
 		SimpleMailMessageItemWriter writer = new SimpleMailMessageItemWriterBuilder().mailSender(this.mailSender)
 				.build();
 
-		writer.write(Arrays.asList(this.items));
+		writer.write(Chunk.of(this.items));
 		verify(this.mailSender).send(this.foo, this.bar);
 	}
 
@@ -86,7 +87,7 @@ class SimpleMailMessageItemWriterBuilderTests {
 		this.mailSender.send(this.foo, this.bar);
 		when(this.mailSender)
 				.thenThrow(new MailSendException(Collections.singletonMap(this.foo, new MessagingException("FOO"))));
-		assertThrows(MailSendException.class, () -> writer.write(List.of(this.items)));
+		assertThrows(MailSendException.class, () -> writer.write(Chunk.of(this.items)));
 	}
 
 	@Test
@@ -103,7 +104,7 @@ class SimpleMailMessageItemWriterBuilderTests {
 		this.mailSender.send(this.foo, this.bar);
 		when(this.mailSender)
 				.thenThrow(new MailSendException(Collections.singletonMap(this.foo, new MessagingException("FOO"))));
-		writer.write(Arrays.asList(this.items));
+		writer.write(Chunk.of(this.items));
 		assertEquals("FOO", content.get());
 	}
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/mail/javamail/MimeMessageItemWriterTests.java

@@ -33,6 +33,8 @@ import jakarta.mail.internet.MimeMessage;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.mail.MailErrorHandler;
 import org.springframework.mail.MailException;
 import org.springframework.mail.MailMessage;
@@ -70,7 +72,7 @@ class MimeMessageItemWriterTests {
 
 		mailSender.send(aryEq(items));
 
-		writer.write(Arrays.asList(items));
+		writer.write(Chunk.of(items));
 
 	}
 
@@ -92,7 +94,7 @@ class MimeMessageItemWriterTests {
 		when(mailSender).thenThrow(new MailSendException(
 				Collections.singletonMap((Object) foo, (Exception) new MessagingException("FOO"))));
 
-		assertThrows(MailSendException.class, () -> writer.write(List.of(items)));
+		assertThrows(MailSendException.class, () -> writer.write(Chunk.of(items)));
 	}
 
 	@Test
@@ -121,7 +123,7 @@ class MimeMessageItemWriterTests {
 		when(mailSender).thenThrow(new MailSendException(
 				Collections.singletonMap((Object) foo, (Exception) new MessagingException("FOO"))));
 
-		writer.write(Arrays.asList(items));
+		writer.write(Chunk.of(items));
 
 		assertEquals("FOO", content.get());
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/AbstractSynchronizedItemStreamWriterTests.java

@@ -26,6 +26,8 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamWriter;
 
@@ -34,6 +36,7 @@ import org.springframework.batch.item.ItemStreamWriter;
  * {@link org.springframework.batch.item.support.builder.SynchronizedItemStreamWriterBuilderTests}
  *
  * @author Dimitrios Liapis
+ * @author Mahmoud Ben Hassine
  *
  */
 @ExtendWith(MockitoExtension.class)
@@ -44,7 +47,7 @@ public abstract class AbstractSynchronizedItemStreamWriterTests {
 
 	private SynchronizedItemStreamWriter<Object> synchronizedItemStreamWriter;
 
-	private final List<Object> testList = Collections.unmodifiableList(new ArrayList<>());
+	private final Chunk<Object> testList = new Chunk<Object>();
 
 	private final ExecutionContext testExecutionContext = new ExecutionContext();
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/ClassifierCompositeItemWriterTests.java

@@ -21,48 +21,52 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.classify.PatternMatchingClassifier;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * @author Dave Syer
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  *
  */
 class ClassifierCompositeItemWriterTests {
 
 	private final ClassifierCompositeItemWriter<String> writer = new ClassifierCompositeItemWriter<>();
 
-	private final List<String> defaults = new ArrayList<>();
+	private final Chunk defaults = new Chunk<>();
 
-	private final List<String> foos = new ArrayList<>();
+	private final Chunk foos = new Chunk<>();
 
 	@Test
 	void testWrite() throws Exception {
-		Map<String, ItemWriter<? super String>> map = new HashMap<>();
+		Map<String, ItemWriter<String>> map = new HashMap<>();
 		ItemWriter<String> fooWriter = new ItemWriter<String>() {
 			@Override
-			public void write(List<? extends String> items) throws Exception {
-				foos.addAll(items);
+			public void write(Chunk<? extends String> chunk) throws Exception {
+				foos.addAll(chunk.getItems());
 			}
 		};
 		ItemWriter<String> defaultWriter = new ItemWriter<String>() {
 			@Override
-			public void write(List<? extends String> items) throws Exception {
-				defaults.addAll(items);
+			public void write(Chunk<? extends String> chunk) throws Exception {
+				defaults.addAll(chunk.getItems());
 			}
 		};
 		map.put("foo", fooWriter);
 		map.put("*", defaultWriter);
-		writer.setClassifier(new PatternMatchingClassifier<>(map));
-		writer.write(Arrays.asList("foo", "foo", "one", "two", "three"));
-		assertEquals("[foo, foo]", foos.toString());
-		assertEquals("[one, two, three]", defaults.toString());
+		writer.setClassifier(new PatternMatchingClassifier(map));
+		writer.write(Chunk.of("foo", "foo", "one", "two", "three"));
+		assertIterableEquals(Chunk.of("foo", "foo"), foos);
+		assertIterableEquals(Chunk.of("one", "two", "three"), defaults);
 	}
 
 	@Test

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/CompositeItemWriterTests.java

@@ -21,6 +21,8 @@ import java.util.Collections;
 import java.util.List;
 
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamWriter;
 import org.springframework.batch.item.ItemWriter;
@@ -30,6 +32,7 @@ import org.springframework.batch.item.ItemWriter;
  *
  * @author Robert Kasanicky
  * @author Will Schipp
+ * @author Mahmoud Ben Hassine
  */
 class CompositeItemWriterTests {
 
@@ -43,7 +46,7 @@ class CompositeItemWriterTests {
 	void testProcess() throws Exception {
 
 		final int NUMBER_OF_WRITERS = 10;
-		List<Object> data = Collections.singletonList(new Object());
+		Chunk<Object> data = Chunk.of(new Object());
 
 		List<ItemWriter<? super Object>> writers = new ArrayList<>();
 
@@ -74,7 +77,7 @@ class CompositeItemWriterTests {
 	private void doTestItemStream(boolean expectOpen) throws Exception {
 		@SuppressWarnings("unchecked")
 		ItemStreamWriter<? super Object> writer = mock(ItemStreamWriter.class);
-		List<Object> data = Collections.singletonList(new Object());
+		Chunk<Object> data = Chunk.of(new Object());
 		ExecutionContext executionContext = new ExecutionContext();
 		if (expectOpen) {
 			writer.open(executionContext);

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/builder/ClassifierCompositeItemWriterBuilderTests.java

@@ -24,35 +24,48 @@ import java.util.Map;
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.item.support.ClassifierCompositeItemWriter;
 import org.springframework.classify.PatternMatchingClassifier;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * @author Glenn Renfro
+ * @author Mahmoud Ben Hassine
  */
 class ClassifierCompositeItemWriterBuilderTests {
 
-	private final List<String> defaults = new ArrayList<>();
+	private final Chunk defaults = new Chunk();
 
-	private final List<String> foos = new ArrayList<>();
+	private final Chunk foos = new Chunk();
 
 	@Test
 	void testWrite() throws Exception {
 		Map<String, ItemWriter<? super String>> map = new HashMap<>();
-		ItemWriter<String> fooWriter = items -> foos.addAll(items);
-		ItemWriter<String> defaultWriter = items -> defaults.addAll(items);
+		ItemWriter<String> fooWriter = new ItemWriter<String>() {
+			@Override
+			public void write(Chunk<? extends String> chunk) throws Exception {
+				foos.addAll(chunk.getItems());
+			}
+		};
+		ItemWriter<String> defaultWriter = new ItemWriter<String>() {
+			@Override
+			public void write(Chunk<? extends String> chunk) throws Exception {
+				defaults.addAll(chunk.getItems());
+			}
+		};
 		map.put("foo", fooWriter);
 		map.put("*", defaultWriter);
 		ClassifierCompositeItemWriter<String> writer = new ClassifierCompositeItemWriterBuilder<String>()
 				.classifier(new PatternMatchingClassifier<>(map)).build();
 
-		writer.write(Arrays.asList("foo", "foo", "one", "two", "three"));
-		assertEquals("[foo, foo]", foos.toString());
-		assertEquals("[one, two, three]", defaults.toString());
+		writer.write(Chunk.of("foo", "foo", "one", "two", "three"));
+		assertIterableEquals(Chunk.of("foo", "foo"), foos);
+		assertIterableEquals(Chunk.of("one", "two", "three"), defaults);
 	}
 
 	@Test

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/support/builder/CompositeItemWriterBuilderTests.java

@@ -22,6 +22,7 @@ import java.util.List;
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamWriter;
 import org.springframework.batch.item.ItemWriter;
@@ -34,6 +35,7 @@ import static org.mockito.Mockito.verify;
 /**
  * @author Glenn Renfro
  * @author Drummond Dawson
+ * @author Mahmoud Ben Hassine
  */
 class CompositeItemWriterBuilderTests {
 
@@ -42,7 +44,7 @@ class CompositeItemWriterBuilderTests {
 	void testProcess() throws Exception {
 
 		final int NUMBER_OF_WRITERS = 10;
-		List<Object> data = Collections.singletonList(new Object());
+		Chunk<Object> data = Chunk.of(new Object());
 
 		List<ItemWriter<? super Object>> writers = new ArrayList<>();
 
@@ -63,7 +65,7 @@ class CompositeItemWriterBuilderTests {
 	@SuppressWarnings("unchecked")
 	void testProcessVarargs() throws Exception {
 
-		List<Object> data = Collections.singletonList(new Object());
+		Chunk<Object> data = Chunk.of(new Object());
 
 		List<ItemWriter<? super Object>> writers = new ArrayList<>();
 
@@ -90,7 +92,7 @@ class CompositeItemWriterBuilderTests {
 	@SuppressWarnings("unchecked")
 	private void ignoreItemStream(boolean ignoreItemStream) throws Exception {
 		ItemStreamWriter<? super Object> writer = mock(ItemStreamWriter.class);
-		List<Object> data = Collections.singletonList(new Object());
+		Chunk<Object> data = Chunk.of(new Object());
 		ExecutionContext executionContext = new ExecutionContext();
 
 		List<ItemWriter<? super Object>> writers = new ArrayList<>();

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/xml/AbstractStaxEventWriterItemWriterTests.java

@@ -30,6 +30,7 @@ import org.xmlunit.diff.DefaultNodeMatcher;
 import org.xmlunit.diff.ElementSelectors;
 import org.xmlunit.matchers.CompareMatcher;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.xml.domain.Trade;
 import org.springframework.batch.support.transaction.ResourcelessTransactionManager;
@@ -60,13 +61,9 @@ abstract class AbstractStaxEventWriterItemWriterTests {
 
 	protected Resource expected = new ClassPathResource("expected-output.xml", getClass());
 
-	protected List<Trade> objects = new ArrayList<Trade>() {
-		{
-			add(new Trade("isin1", 1, new BigDecimal(1.0), "customer1"));
-			add(new Trade("isin2", 2, new BigDecimal(2.0), "customer2"));
-			add(new Trade("isin3", 3, new BigDecimal(3.0), "customer3"));
-		}
-	};
+	protected Chunk<Trade> objects = Chunk.of(new Trade("isin1", 1, new BigDecimal(1.0), "customer1"),
+			new Trade("isin2", 2, new BigDecimal(2.0), "customer2"),
+			new Trade("isin3", 3, new BigDecimal(3.0), "customer3"));
 
 	/**
 	 * Write list of domain objects and check the output file.

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/xml/Jaxb2NamespaceMarshallingTests.java

@@ -30,6 +30,7 @@ import org.junit.jupiter.api.Test;
 import org.xmlunit.builder.Input;
 import org.xmlunit.matchers.CompareMatcher;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.xml.domain.QualifiedTrade;
 import org.springframework.batch.support.transaction.ResourcelessTransactionManager;
@@ -62,7 +63,7 @@ class Jaxb2NamespaceMarshallingTests {
 
 	private final Resource expected = new ClassPathResource("expected-qualified-output.xml", getClass());
 
-	private final List<QualifiedTrade> objects = List.of(
+	private final Chunk<QualifiedTrade> objects = Chunk.of(
 			new QualifiedTrade("isin1", 1, new BigDecimal(1.0), "customer1"),
 			new QualifiedTrade("isin2", 2, new BigDecimal(2.0), "customer2"),
 			new QualifiedTrade("isin3", 3, new BigDecimal(3.0), "customer3"));

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/xml/StaxEventItemWriterTests.java

@@ -29,6 +29,7 @@ import org.apache.commons.io.FileUtils;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.UnexpectedInputException;
 import org.springframework.batch.item.WriterNotOpenException;
@@ -87,11 +88,11 @@ class StaxEventItemWriterTests {
 		}
 	};
 
-	private final List<?> items = List.of(item);
+	private final Chunk<?> items = Chunk.of(item);
 
-	private final List<?> itemsMultiByte = List.of(itemMultiByte);
+	private final Chunk<?> itemsMultiByte = Chunk.of(itemMultiByte);
 
-	private final List<?> jaxbItems = List.of(jaxbItem);
+	private final Chunk<?> jaxbItems = Chunk.of(jaxbItem);
 
 	private static final String TEST_STRING = "<" + ClassUtils.getShortName(StaxEventItemWriter.class)
 			+ "-testString/>";
@@ -138,7 +139,7 @@ class StaxEventItemWriterTests {
 	void testAssertWriterIsInitialized() {
 		StaxEventItemWriter<String> writer = new StaxEventItemWriter<>();
 
-		assertThrows(WriterNotOpenException.class, () -> writer.write(List.of("foo")));
+		assertThrows(WriterNotOpenException.class, () -> writer.write(Chunk.of("foo")));
 	}
 
 	@Test

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/xml/TransactionalStaxEventItemWriterTests.java

@@ -31,6 +31,8 @@ import javax.xml.transform.Result;
 import org.apache.commons.io.FileUtils;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.support.transaction.ResourcelessTransactionManager;
 import org.springframework.core.io.FileSystemResource;
@@ -67,7 +69,7 @@ class TransactionalStaxEventItemWriterTests {
 		}
 	};
 
-	private final List<?> items = List.of(item);
+	private final Chunk<?> items = Chunk.of(item);
 
 	private static final String TEST_STRING = "<!--" + ClassUtils.getShortName(StaxEventItemWriter.class)
 			+ "-testString-->";

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/xml/builder/StaxEventItemWriterBuilderTests.java

@@ -30,6 +30,7 @@ import org.apache.commons.io.FileUtils;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.batch.item.xml.StaxEventItemWriter;
@@ -54,7 +55,7 @@ class StaxEventItemWriterBuilderTests {
 
 	private WritableResource resource;
 
-	private List<Foo> items;
+	private Chunk<Foo> items;
 
 	private Marshaller marshaller;
 
@@ -73,7 +74,7 @@ class StaxEventItemWriterBuilderTests {
 		this.resource = new FileSystemResource(
 				File.createTempFile("StaxEventItemWriterBuilderTests", ".xml", directory));
 
-		this.items = new ArrayList<>(3);
+		this.items = new Chunk<>();
 		this.items.add(new Foo(1, "two", "three"));
 		this.items.add(new Foo(4, "five", "six"));
 		this.items.add(new Foo(7, "eight", "nine"));
@@ -99,7 +100,7 @@ class StaxEventItemWriterBuilderTests {
 
 		staxEventItemWriter.afterPropertiesSet();
 		staxEventItemWriter.open(executionContext);
-		staxEventItemWriter.write(Collections.emptyList());
+		staxEventItemWriter.write(new Chunk<Foo>());
 		staxEventItemWriter.update(executionContext);
 		staxEventItemWriter.close();
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/repeat/support/AbstractTradeBatchTests.java

@@ -19,6 +19,8 @@ package org.springframework.batch.repeat.support;
 import java.util.List;
 
 import org.junit.jupiter.api.BeforeEach;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.item.file.FlatFileItemReader;
@@ -33,6 +35,7 @@ import org.springframework.core.io.Resource;
  * Base class for simple tests with small trade data set.
  *
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  *
  */
 abstract class AbstractTradeBatchTests {
@@ -81,7 +84,7 @@ abstract class AbstractTradeBatchTests {
 		// This has to be synchronized because we are going to test the state
 		// (count) at the end of a concurrent batch run.
 		@Override
-		public synchronized void write(List<? extends Trade> data) {
+		public synchronized void write(Chunk<? extends Trade> data) {
 			count++;
 			System.out.println("Executing trade '" + data + "'");
 		}

spring-batch-infrastructure/src/test/java/org/springframework/batch/repeat/support/ItemReaderRepeatCallback.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@ package org.springframework.batch.repeat.support;
 
 import java.util.Collections;
 
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemReader;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.repeat.RepeatStatus;
@@ -25,6 +26,7 @@ import org.springframework.batch.repeat.RepeatContext;
 
 /**
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  *
  */
 public class ItemReaderRepeatCallback<T> implements RepeatCallback {
@@ -55,7 +57,7 @@ public class ItemReaderRepeatCallback<T> implements RepeatCallback {
 		if (item == null) {
 			return RepeatStatus.FINISHED;
 		}
-		writer.write(Collections.singletonList(item));
+		writer.write(Chunk.of(item));
 		return RepeatStatus.CONTINUABLE;
 	}
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/repeat/support/TaskExecutorRepeatTemplateAsynchronousTests.java

@@ -30,6 +30,8 @@ import java.util.List;
 import java.util.Set;
 
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.repeat.RepeatCallback;
 import org.springframework.batch.repeat.RepeatContext;
@@ -148,7 +150,7 @@ class TaskExecutorRepeatTemplateAsynchronousTests extends AbstractTradeBatchTest
 				Thread.sleep(100);
 				Trade item = provider.read();
 				if (item != null) {
-					processor.write(Collections.singletonList(item));
+					processor.write(Chunk.of(item));
 				}
 				return RepeatStatus.continueIf(item != null);
 			}
@@ -184,7 +186,7 @@ class TaskExecutorRepeatTemplateAsynchronousTests extends AbstractTradeBatchTest
 				threadNames.add(Thread.currentThread().getName() + " : " + item);
 				items.add("" + item);
 				if (item != null) {
-					processor.write(Collections.singletonList(item));
+					processor.write(Chunk.of(item));
 					// Do some more I/O
 					for (int i = 0; i < 10; i++) {
 						TradeItemReader provider = new TradeItemReader(resource);

spring-batch-infrastructure/src/test/java/org/springframework/batch/retry/jms/ExternalRetryTests.java

@@ -18,6 +18,8 @@ package org.springframework.batch.retry.jms;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.item.Chunk;
 import org.springframework.batch.item.ItemReader;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -96,7 +98,7 @@ class ExternalRetryTests {
 
 		final ItemWriter<Object> writer = new ItemWriter<Object>() {
 			@Override
-			public void write(final List<?> texts) {
+			public void write(final Chunk<?> texts) {
 
 				for (Object text : texts) {
 
@@ -115,7 +117,7 @@ class ExternalRetryTests {
 					try {
 						final Object item = provider.read();
 						RetryCallback<Object, Exception> callback = context -> {
-							writer.write(Collections.singletonList(item));
+							writer.write(Chunk.of(item));
 							return null;
 						};
 						return retryTemplate.execute(callback, new DefaultRetryState(item));
@@ -137,7 +139,7 @@ class ExternalRetryTests {
 					RetryCallback<Object, Exception> callback = new RetryCallback<Object, Exception>() {
 						@Override
 						public Object doWithRetry(RetryContext context) throws Exception {
-							writer.write(Collections.singletonList(item));
+							writer.write(Chunk.of(item));
 							return null;
 						}
 					};