DATAJPA-562 - Support for pluggable generic post-processing of JPA Query results.

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-jpa</artifactId>
-	<version>1.7.0.BUILD-SNAPSHOT</version>
+	<version>1.7.0.DATAJPA-562-SNAPSHOT</version>
 
 	<name>Spring Data JPA</name>
 	<description>Spring Data module for JPA repositories.</description>

src/main/java/org/springframework/data/jpa/repository/support/DetachingJpaResultPostProcessor.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2008-2014 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.data.jpa.repository.support;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.persistence.EntityManager;
+
+import org.springframework.util.Assert;
+
+/**
+ * A {@link JpaResultPostProcessor} that potentially detaches resulting Domain-Objects from the configured
+ * {@link EntityManager}.
+ * 
+ * @author Thomas Darimont
+ */
+public class DetachingJpaResultPostProcessor implements JpaResultPostProcessor {
+
+	private final EntityManager em;
+
+	/**
+	 * Creates a new {@link DetachingJpaResultPostProcessor}.
+	 * 
+	 * @param em must not be {@literal null}.
+	 */
+	public DetachingJpaResultPostProcessor(EntityManager em) {
+
+		Assert.notNull(em, "EntityManager must not be null!");
+
+		this.em = em;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.jpa.repository.support.JpaResultPostProcessor#postProcessResult(java.lang.Class, java.lang.Object)
+	 */
+	@Override
+	public <T, R> R postProcessResult(Class<T> domainClass, R entity) {
+
+		if (domainClass.isInstance(entity)) {
+			em.detach(entity);
+		}
+
+		return entity;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.jpa.repository.support.JpaResultPostProcessor#postProcessResults(java.lang.Class, java.util.List)
+	 */
+	@Override
+	public <T> List<T> postProcessResults(Class<T> domainClass, List<T> results) {
+
+		List<T> postProcessedResults = new ArrayList<T>();
+
+		for (T entity : results) {
+			if (domainClass.isInstance(entity)) {
+				postProcessedResults.add(postProcessResult(domainClass, entity));
+			}
+		}
+
+		return postProcessedResults;
+	}
+}

src/main/java/org/springframework/data/jpa/repository/support/JpaRepositoryFactory.java

@@ -35,25 +35,38 @@
  * JPA specific generic repository factory.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class JpaRepositoryFactory extends RepositoryFactorySupport {
 
 	private final EntityManager entityManager;
 	private final QueryExtractor extractor;
 	private final CrudMethodMetadataPostProcessor lockModePostProcessor;
+	private final JpaResultPostProcessor jpaResultPostProcessor;
 
 	/**
 	 * Creates a new {@link JpaRepositoryFactory}.
 	 * 
 	 * @param entityManager must not be {@literal null}
 	 */
 	public JpaRepositoryFactory(EntityManager entityManager) {
+		this(entityManager, NoopJpaResultPostProcessor.INSTANCE);
+	}
+
+	/**
+	 * Creates a new {@link JpaRepositoryFactory}.
+	 * 
+	 * @param entityManager must not be {@literal null}
+	 * @param evaluationContextProvider must not be {@literal null}
+	 */
+	public JpaRepositoryFactory(EntityManager entityManager, JpaResultPostProcessor jpaResultPostProcessor) {
 
 		Assert.notNull(entityManager);
 
 		this.entityManager = entityManager;
 		this.extractor = PersistenceProvider.fromEntityManager(entityManager);
 		this.lockModePostProcessor = CrudMethodMetadataPostProcessor.INSTANCE;
+		this.jpaResultPostProcessor = jpaResultPostProcessor;
 
 		addRepositoryProxyPostProcessor(lockModePostProcessor);
 	}
@@ -68,6 +81,10 @@ protected Object getTargetRepository(RepositoryMetadata metadata) {
 		SimpleJpaRepository<?, ?> repository = getTargetRepository(metadata, entityManager);
 		repository.setRepositoryMethodMetadata(lockModePostProcessor.getLockMetadataProvider());
 
+		if (jpaResultPostProcessor != null) {
+			repository.setJpaResultPostProcessor(jpaResultPostProcessor);
+		}
+
 		return repository;
 	}
 

src/main/java/org/springframework/data/jpa/repository/support/JpaRepositoryFactoryBean.java

@@ -37,7 +37,9 @@
 public class JpaRepositoryFactoryBean<T extends Repository<S, ID>, S, ID extends Serializable> extends
 		TransactionalRepositoryFactoryBeanSupport<T, S, ID> {
 
-	private EntityManager entityManager;
+	protected EntityManager entityManager;
+
+	private JpaResultPostProcessor jpaResultPostProcessor;
 
 	/**
 	 * The {@link EntityManager} to be used.
@@ -58,6 +60,16 @@ public void setMappingContext(MappingContext<?, ?> mappingContext) {
 		super.setMappingContext(mappingContext);
 	}
 
+	/**
+	 * The {@link JpaResultPostProcessor} to be used.
+	 * 
+	 * @param jpaResultPostProcessor the jpaResultPostProcessor to set.
+	 * @since 1.7
+	 */
+	public void setJpaResultPostProcessor(JpaResultPostProcessor jpaResultPostProcessor) {
+		this.jpaResultPostProcessor = jpaResultPostProcessor;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * 
@@ -76,7 +88,7 @@ protected RepositoryFactorySupport doCreateRepositoryFactory() {
 	 * @return
 	 */
 	protected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager) {
-		return new JpaRepositoryFactory(entityManager);
+		return new JpaRepositoryFactory(entityManager, jpaResultPostProcessor);
 	}
 
 	/*

src/main/java/org/springframework/data/jpa/repository/support/JpaResultPostProcessor.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2008-2014 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.data.jpa.repository.support;
+
+import java.util.List;
+
+/**
+ * A {@link JpaResultPostProcessor} allows to post-process a single or multiple entity result.
+ * 
+ * @author Thomas Darimont
+ */
+public interface JpaResultPostProcessor {
+
+	/**
+	 * @param domainClass
+	 * @param entity
+	 * @return
+	 */
+	<T, R> R postProcessResult(Class<T> domainClass, R entity);
+
+	/**
+	 * @param domainClass
+	 * @param results
+	 * @return
+	 */
+	<T> List<T> postProcessResults(Class<T> domainClass, List<T> results);
+}

src/main/java/org/springframework/data/jpa/repository/support/NoopJpaResultPostProcessor.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2008-2014 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.data.jpa.repository.support;
+
+import java.util.List;
+
+/**
+ * A {@link JpaResultPostProcessor} that simply returns the results as is.
+ * 
+ * @author Thomas Darimont
+ */
+enum NoopJpaResultPostProcessor implements JpaResultPostProcessor {
+
+	INSTANCE;
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.jpa.repository.support.JpaResultPostProcessor#postProcessResult(java.lang.Class, java.lang.Object)
+	 */
+	@Override
+	public <T, R> R postProcessResult(Class<T> domainClass, R entity) {
+		return entity;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.jpa.repository.support.JpaResultPostProcessor#postProcessResults(java.lang.Class, java.util.List)
+	 */
+	@Override
+	public <T> List<T> postProcessResults(Class<T> domainClass, List<T> results) {
+		return results;
+	}
+}