OPEN - issue BATCH-320: Refactor ItemWriter as primary collaborator (with wrapper for processor)

http://jira.springframework.org/browse/BATCH-320

Half way there - tests OK, but some naming and tidying up to do.

spring-batch-infrastructure/src/main/java/org/springframework/batch/io/support/HibernateAwareItemWriter.java

@@ -114,10 +114,11 @@ public class HibernateAwareItemWriter implements ItemWriter, RepeatInterceptor,
 	/**
 	 * Use the delegate to actually do the writing, but flush aggressively if
 	 * the item was previously part of a failed chunk.
+	 * @throws Exception 
 	 * 
 	 * @see org.springframework.batch.io.OutputSource#write(java.lang.Object)
 	 */
-	public void write(Object output) {
+	public void write(Object output) throws Exception {
 		getProcessed().add(output);
 		delegate.write(output);
 		flushIfNecessary(output);

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

@@ -31,6 +31,7 @@ public interface ItemWriter {
 	 * 
 	 * @param item
 	 *            the object to write.
+	 * @throws Exception if something goes wrong
 	 */
-	public void write(Object item);
+	public void write(Object item) throws Exception;
 }

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

@@ -8,6 +8,7 @@ import java.util.Properties;
 
 import org.springframework.batch.item.ItemProcessor;
 import org.springframework.batch.item.ItemReader;
+import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.restart.GenericRestartData;
 import org.springframework.batch.restart.RestartData;
 import org.springframework.batch.restart.Restartable;
@@ -17,18 +18,18 @@ import org.springframework.batch.restart.Restartable;
  * 
  * @author Robert Kasanicky
  */
-public class CompositeItemProcessor implements ItemProcessor, Restartable {
+public class CompositeItemWriter implements ItemWriter, Restartable {
 
 	private static final String SEPARATOR = "#";
 
-	private List itemProcessors;
+	private List delegates;
 
 	/**
 	 * Calls injected ItemProcessors in order.
 	 */
-	public void process(Object data) throws Exception {
-		for (Iterator iterator = itemProcessors.listIterator(); iterator.hasNext();) {
-			((ItemProcessor) iterator.next()).process(data);
+	public void write(Object data) throws Exception {
+		for (Iterator iterator = delegates.listIterator(); iterator.hasNext();) {
+			((ItemWriter) iterator.next()).write(data);
 		}
 	}
 
@@ -63,24 +64,24 @@ public class CompositeItemProcessor implements ItemProcessor, Restartable {
 		List restartDataList = parseProperties(data.getProperties());
 
 		// iterators would make the loop below less readable
-		for (int i = 0; i < itemProcessors.size(); i++) {
-			if (itemProcessors.get(i) instanceof Restartable) {
-				((Restartable) itemProcessors.get(i)).restoreFrom((RestartData) restartDataList.get(i));
+		for (int i = 0; i < delegates.size(); i++) {
+			if (delegates.get(i) instanceof Restartable) {
+				((Restartable) delegates.get(i)).restoreFrom((RestartData) restartDataList.get(i));
 			}
 		}
 
 	}
 
-	public void setItemProcessors(List itemProcessors) {
-		this.itemProcessors = itemProcessors;
+	public void setItemWriters(List itemProcessors) {
+		this.delegates = itemProcessors;
 	}
 
 	/**
 	 * Parses compound properties into a list of RestartData.
 	 */
 	private List parseProperties(Properties props) {
-		List restartDataList = new ArrayList(itemProcessors.size());
-		for (int i = 0; i < itemProcessors.size(); i++) {
+		List restartDataList = new ArrayList(delegates.size());
+		for (int i = 0; i < delegates.size(); i++) {
 			restartDataList.add(new GenericRestartData(new Properties()));
 		}
 
@@ -104,7 +105,7 @@ public class CompositeItemProcessor implements ItemProcessor, Restartable {
 	private Properties createCompoundProperties(PropertiesExtractor extractor) {
 		Properties stats = new Properties();
 		int index = 0;
-		for (Iterator iterator = itemProcessors.listIterator(); iterator.hasNext();) {
+		for (Iterator iterator = delegates.listIterator(); iterator.hasNext();) {
 			ItemProcessor processor = (ItemProcessor) iterator.next();
 			Properties processorStats = extractor.extractProperties(processor);
 			if (processorStats != null) {

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

@@ -3,7 +3,6 @@ package org.springframework.batch.item.processor;
 import java.util.Properties;
 
 import org.springframework.batch.io.Skippable;
-import org.springframework.batch.item.ItemProcessor;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.restart.GenericRestartData;
 import org.springframework.batch.restart.RestartData;
@@ -18,17 +17,18 @@ import org.springframework.util.Assert;
  * @author Dave Syer
  * @author Robert Kasanicky
  */
-public class ItemWriterItemProcessor implements ItemProcessor, Restartable, Skippable, InitializingBean {
+public class DelegatingItemWriter implements ItemWriter, Restartable, Skippable, InitializingBean {
 
 	private ItemWriter writer;
 
 	/**
 	 * Calls {@link #doProcess(Object)} and then writes the result to the
-	 * {@link ItemWriter}.
+	 * delegate {@link ItemWriter}.
+	 * @throws Exception 
 	 * 
 	 * @see org.springframework.batch.item.ItemProcessor#process(java.lang.Object)
 	 */
-	final public void process(Object item) throws Exception {
+	final public void write(Object item) throws Exception {
 		Object result = doProcess(item);
 		writer.write(result);
 	}
@@ -36,6 +36,7 @@ public class ItemWriterItemProcessor implements ItemProcessor, Restartable, Skip
 	/**
 	 * By default returns the argument. This method is an extension point meant
 	 * to be overridden by subclasses that implement processing logic.
+	 * @throws Exception 
 	 */
 	protected Object doProcess(Object item) throws Exception {
 		return item;
@@ -44,7 +45,7 @@ public class ItemWriterItemProcessor implements ItemProcessor, Restartable, Skip
 	/**
 	 * Setter for {@link ItemWriter}.
 	 */
-	public void setItemWriter(ItemWriter writer) {
+	public void setDelegate(ItemWriter writer) {
 		this.writer = writer;
 	}
 

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

@@ -24,7 +24,7 @@ import org.springframework.batch.support.AbstractMethodInvokingDelegator;
  * Delegates item processing to a custom method - 
  * passes the item as an argument for the delegate method.
  * 
- * @see PropertyExtractingDelegatingItemProcessor
+ * @see PropertyExtractingDelegatingItemWriter
  * 
  * @author Robert Kasanicky
  */

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

@@ -9,7 +9,7 @@ import org.springframework.util.Assert;
  * 
  * @author Robert Kasanicky
  */
-public class TransformerWriterItemProcessor extends ItemWriterItemProcessor {
+public class ItemTransformerItemWriterr extends DelegatingItemWriter {
 
 	private ItemTransformer itemTransformer;
 

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

@@ -16,7 +16,7 @@
 
 package org.springframework.batch.item.processor;
 
-import org.springframework.batch.item.ItemProcessor;
+import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.support.AbstractMethodInvokingDelegator;
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.BeanWrapperImpl;
@@ -30,7 +30,7 @@ import org.springframework.util.Assert;
  * 
  * @author Robert Kasanicky
  */
-public class PropertyExtractingDelegatingItemProcessor extends AbstractMethodInvokingDelegator implements ItemProcessor {
+public class PropertyExtractingDelegatingItemWriter extends AbstractMethodInvokingDelegator implements ItemWriter {
 	
 	private String[] fieldsUsedAsTargetMethodArguments;
 	
@@ -38,7 +38,7 @@ public class PropertyExtractingDelegatingItemProcessor extends AbstractMethodInv
 	 * Extracts values from item's fields named in fieldsUsedAsTargetMethodArguments
 	 * and passes them as arguments to the delegate method.
 	 */
-	public void process(Object item) throws Exception {
+	public void write(Object item) throws Exception {
 		// helper for extracting property values from a bean
 		BeanWrapper beanWrapper = new BeanWrapperImpl();
 		beanWrapper.setWrappedInstance(item);

spring-batch-infrastructure/src/main/java/org/springframework/batch/repeat/callback/ItemReaderRepeatCallback.java

@@ -16,15 +16,15 @@
 
 package org.springframework.batch.repeat.callback;
 
-import org.springframework.batch.item.ItemProcessor;
 import org.springframework.batch.item.ItemReader;
+import org.springframework.batch.item.ItemWriter;
+import org.springframework.batch.repeat.ExitStatus;
 import org.springframework.batch.repeat.RepeatCallback;
 import org.springframework.batch.repeat.RepeatContext;
-import org.springframework.batch.repeat.ExitStatus;
 
 /**
  * Simple wrapper for two business interfaces: get the next item from a
- * ItemProvider and apply the given processor to the result (if not null).
+ * reader and apply the given writer to the result (if not null).
  * 
  * @author Dave Syer
  * 
@@ -33,12 +33,12 @@ public class ItemReaderRepeatCallback implements RepeatCallback {
 
 	ItemReader provider;
 
-	ItemProcessor processor;
+	ItemWriter writer;
 
-	public ItemReaderRepeatCallback(ItemReader provider, ItemProcessor processor) {
+	public ItemReaderRepeatCallback(ItemReader provider, ItemWriter writer) {
 		super();
 		this.provider = provider;
-		this.processor = processor;
+		this.writer = writer;
 	}
 
 	/**
@@ -52,7 +52,7 @@ public class ItemReaderRepeatCallback implements RepeatCallback {
 	}
 
 	/**
-	 * Use the processor to process the next item if there is one. Return the
+	 * Use the writer to process the next item if there is one. Return the
 	 * item processed, or null if nothing was available.
 	 * @see org.springframework.batch.repeat.RepeatCallback#doInIteration(org.springframework.batch.item.BatchContextAdapter)
 	 * @param context the current context.
@@ -63,9 +63,9 @@ public class ItemReaderRepeatCallback implements RepeatCallback {
 		ExitStatus result = ExitStatus.FINISHED;
 		Object item = provider.read();
 
-		if (processor != null) {
+		if (writer != null) {
 			if (item != null) {
-				processor.process(item);
+				writer.write(item);
 				result = ExitStatus.CONTINUABLE;
 			}
 			item = null;

spring-batch-infrastructure/src/main/java/org/springframework/batch/retry/callback/ItemReaderRetryCallback.java

@@ -18,9 +18,9 @@ package org.springframework.batch.retry.callback;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.springframework.batch.item.ItemProcessor;
 import org.springframework.batch.item.ItemReader;
 import org.springframework.batch.item.ItemRecoverer;
+import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.retry.RetryCallback;
 import org.springframework.batch.retry.RetryContext;
 import org.springframework.batch.retry.RetryPolicy;
@@ -49,15 +49,15 @@ public class ItemReaderRetryCallback implements RetryCallback {
 
 	private ItemReader provider;
 
-	private ItemProcessor processor;
+	private ItemWriter writer;
 
 	private ItemRecoverer recoverer;
 
 	public ItemReaderRetryCallback(ItemReader provider,
-			ItemProcessor processor) {
+			ItemWriter writer) {
 		super();
 		this.provider = provider;
-		this.processor = processor;
+		this.writer = writer;
 	}
 
 	/**
@@ -99,7 +99,7 @@ public class ItemReaderRetryCallback implements RetryCallback {
 	private Object process(RetryContext context) throws Exception {
 		Object item = next(context);
 		if (item != null) {
-			processor.process(item);
+			writer.write(item);
 		}
 		context.removeAttribute(ITEM); // if successful
 		return item;