Created builder for HibernateCursorItemReader

This commit creates a builder for the HibernateCursorItemReader

Resolves BATCH-2584

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2013 the original author or authors.
+ * Copyright 2006-2017 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.
@@ -57,7 +57,7 @@ import org.springframework.util.ClassUtils;
 public class HibernateCursorItemReader<T> extends AbstractItemCountingItemStreamItemReader<T> 
         implements InitializingBean {
 
-	private HibernateItemReaderHelper<T> helper = new HibernateItemReaderHelper<T>();
+	private HibernateItemReaderHelper<T> helper = new HibernateItemReaderHelper<>();
 
 	public HibernateCursorItemReader() {
 		setName(ClassUtils.getShortName(HibernateCursorItemReader.class));

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

@@ -0,0 +1,251 @@
+/*
+ * Copyright 2017 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
+ *
+ *      http://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.database.builder;
+
+import java.util.Map;
+
+import org.hibernate.SessionFactory;
+
+import org.springframework.batch.item.database.HibernateCursorItemReader;
+import org.springframework.batch.item.database.orm.HibernateQueryProvider;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * This is a builder for the {@link HibernateCursorItemReader}.  When configuring, one of
+ * the following should be provided:
+ * <ul>
+ *     <li>{@link #queryString(String)}</li>
+ *     <li>{@link #queryName(String)}</li>
+ *     <li>{@link #queryProvider(HibernateQueryProvider)}</li>
+ * </ul>
+ *
+ * @author Michael Minella
+ * @since 4.0
+ * @see HibernateCursorItemReader
+ */
+public class HibernateCursorItemReaderBuilder<T> {
+
+	private Map<String, Object> parameterValues;
+
+	private String queryName;
+
+	private int fetchSize;
+
+	private HibernateQueryProvider queryProvider;
+
+	private String queryString;
+
+	private SessionFactory sessionFactory;
+
+	private boolean useStatelessSession;
+
+	private int currentItem;
+
+	private int maxItemCount = Integer.MAX_VALUE;
+
+	private boolean saveState = true;
+
+	private String name;
+
+	/**
+	 * A name used to prevent key collisions while saving the state in the
+	 * {@link org.springframework.batch.item.ExecutionContext}
+	 *
+	 * @param name unique name for this reader instance
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setName(String)
+	 */
+	public HibernateCursorItemReaderBuilder<T> name(String name) {
+		this.name = name;
+
+		return this;
+	}
+
+	/**
+	 * A map of parameter values to be set on the query.   The key of the map is the name
+	 * of the parameter to be set with the value being the value to be set.
+	 *
+	 * @param parameterValues map of values
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setParameterValues(Map)
+	 */
+	public HibernateCursorItemReaderBuilder<T> parameterValues(Map<String, Object> parameterValues) {
+		this.parameterValues = parameterValues;
+
+		return this;
+	}
+
+	/**
+	 * The name of the Hibernate named query to be executed for this reader.
+	 *
+	 * @param queryName name of the query to execute
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setQueryName(String)
+	 */
+	public HibernateCursorItemReaderBuilder<T> queryName(String queryName) {
+		this.queryName = queryName;
+
+		return this;
+	}
+
+	/**
+	 * The number of items to be returned with each round trip to the database.  Used
+	 * internally by Hibernate.
+	 *
+	 * @param fetchSize number of records to return per fetch
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setFetchSize(int)
+	 */
+	public HibernateCursorItemReaderBuilder<T> fetchSize(int fetchSize) {
+		this.fetchSize = fetchSize;
+
+		return this;
+	}
+
+	/**
+	 * A query provider.  This should be set only if {@link #queryString(String)} and
+	 * {@link #queryName(String)} have not been set.
+	 *
+	 * @param queryProvider the query provider
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setQueryProvider(HibernateQueryProvider)
+	 */
+	public HibernateCursorItemReaderBuilder<T> queryProvider(HibernateQueryProvider queryProvider) {
+		this.queryProvider = queryProvider;
+
+		return this;
+	}
+
+	/**
+	 * The HQL query string to execute.  This should only be set if
+	 * {@link #queryProvider(HibernateQueryProvider)} and {@link #queryName(String)} have
+	 * not been set.
+	 *
+	 * @param queryString the HQL query
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setQueryString(String)
+	 */
+	public HibernateCursorItemReaderBuilder<T> queryString(String queryString) {
+		this.queryString = queryString;
+
+		return this;
+	}
+
+	/**
+	 * The Hibernate {@link SessionFactory} to execute the query against.
+	 *
+	 * @param sessionFactory the session factorry
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setSessionFactory(SessionFactory)
+	 */
+	public HibernateCursorItemReaderBuilder<T> sessionFactory(SessionFactory sessionFactory) {
+		this.sessionFactory = sessionFactory;
+
+		return this;
+	}
+
+	/**
+	 * Indicator for whether to use a {@link org.hibernate.StatelessSession}
+	 * (<code>true</code>) or a {@link org.hibernate.Session} (<code>false</code>).
+	 *
+	 * @param useStatelessSession Defaults to false
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setUseStatelessSession(boolean)
+	 */
+	public HibernateCursorItemReaderBuilder<T> useSatelessSession(boolean useStatelessSession) {
+		this.useStatelessSession = useStatelessSession;
+
+		return this;
+	}
+
+	/**
+	 * Index for the current item.  Used on restarts to indicate where to start from.
+	 *
+	 * @param currentItem current index
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setCurrentItemCount(int)
+	 */
+	public HibernateCursorItemReaderBuilder<T> currentItem(int currentItem) {
+		this.currentItem = currentItem;
+
+		return this;
+	}
+
+	/**
+	 * The index of the max item to be read.
+	 *
+	 * @param maxItemCount max index
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setMaxItemCount(int)
+	 */
+	public HibernateCursorItemReaderBuilder<T> maxItemCount(int maxItemCount) {
+		this.maxItemCount = maxItemCount;
+
+		return this;
+	}
+
+	/**
+	 * Indicates if the state should be saved.  If set to false, restarts will begin at
+	 * the beginning of the dataset.  Defaults to true
+	 *
+	 * @param saveState indicator
+	 * @return this instance for method chaining
+	 * @see HibernateCursorItemReader#setSaveState(boolean)
+	 */
+	public HibernateCursorItemReaderBuilder<T> saveState(boolean saveState) {
+		this.saveState = saveState;
+
+		return this;
+	}
+
+	/**
+	 * Returns a fully constructed {@link HibernateCursorItemReader}.
+	 *
+	 * @return a new {@link HibernateCursorItemReader}
+	 */
+	public HibernateCursorItemReader<T> build() {
+		Assert.state(this.fetchSize >= 0, "fetchSize must not be negative");
+		Assert.state(this.sessionFactory != null, "A SessionFactory must be provided");
+
+		if(this.saveState) {
+			Assert.state(StringUtils.hasText(this.name),
+					"A name is required when saveState is set to true.");
+		}
+
+		if (queryProvider == null) {
+			Assert.state(StringUtils.hasText(queryString) ^ StringUtils.hasText(queryName),
+					"queryString or queryName must be set");
+		}
+
+		HibernateCursorItemReader<T> reader = new HibernateCursorItemReader<>();
+
+		reader.setFetchSize(this.fetchSize);
+		reader.setParameterValues(this.parameterValues);
+		reader.setQueryName(this.queryName);
+		reader.setQueryProvider(this.queryProvider);
+		reader.setQueryString(this.queryString);
+		reader.setSessionFactory(this.sessionFactory);
+		reader.setUseStatelessSession(this.useStatelessSession);
+		reader.setCurrentItemCount(this.currentItem);
+		reader.setMaxItemCount(this.maxItemCount);
+		reader.setName(this.name);
+		reader.setSaveState(this.saveState);
+
+		return reader;
+	}
+
+ }