| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.batchee.extras.jpa; |
| |
| import org.apache.batchee.doc.api.Documentation; |
| import org.apache.batchee.extras.locator.BeanLocator; |
| |
| import javax.batch.api.BatchProperty; |
| import javax.batch.api.chunk.ItemReader; |
| import javax.batch.operations.BatchRuntimeException; |
| import javax.inject.Inject; |
| import javax.persistence.EntityManager; |
| import javax.persistence.Query; |
| import java.io.Serializable; |
| import java.util.Collection; |
| import java.util.LinkedList; |
| import java.util.List; |
| |
| @Documentation("Read JPA entities from a query.") |
| public class JpaItemReader extends EntityManagerLocator implements ItemReader { |
| @Inject |
| @BatchProperty |
| @Documentation("The parameter provider ref or qualified name") |
| private String parameterProvider; |
| |
| @Inject |
| @BatchProperty |
| @Documentation("The named query to execute") |
| private String namedQuery; |
| |
| @Inject |
| @BatchProperty |
| @Documentation("The query to execute if the named query is empty") |
| private String query; |
| |
| @Inject |
| @BatchProperty |
| @Documentation("Pagination size") |
| private String pageSize; |
| |
| @Inject |
| @BatchProperty |
| @Documentation("Should entities be detached (default false)") |
| private String detachEntities; |
| |
| @Inject |
| @BatchProperty |
| @Documentation("Should JPA transaction be used (default false)") |
| private String jpaTransaction; |
| |
| private int page = 10; |
| private int firstResult = 0; |
| private BeanLocator.LocatorInstance<EntityManagerProvider> emProvider; |
| private BeanLocator.LocatorInstance<ParameterProvider> paramProvider = null; |
| private LinkedList<Object> items = new LinkedList<Object>(); |
| private boolean detach; |
| private boolean transaction; |
| |
| @Override |
| public void open(final Serializable checkpoint) throws Exception { |
| final BeanLocator beanLocator = BeanLocator.Finder.get(locator); |
| |
| emProvider = findEntityManager(); |
| if (parameterProvider != null) { |
| paramProvider = beanLocator.newInstance(ParameterProvider.class, parameterProvider); |
| } |
| if (pageSize != null) { |
| page = Integer.parseInt(pageSize, page); |
| } |
| if (namedQuery == null && query == null) { |
| throw new BatchRuntimeException("a query should be provided"); |
| } |
| detach = Boolean.parseBoolean(detachEntities); |
| transaction = Boolean.parseBoolean(jpaTransaction); |
| } |
| |
| @Override |
| public void close() throws Exception { |
| if (emProvider != null) { |
| emProvider.release(); |
| } |
| if (paramProvider != null) { |
| paramProvider.release(); |
| } |
| } |
| |
| @Override |
| public Object readItem() throws Exception { |
| if (items.isEmpty()) { |
| final Collection<?> objects = nextPage(); |
| if (objects == null || objects.isEmpty()) { |
| return null; |
| } |
| |
| items.addAll(objects); |
| firstResult += items.size(); |
| } |
| return items.pop(); |
| } |
| |
| private Collection<?> nextPage() { |
| final EntityManager em = emProvider.getValue().newEntityManager(); |
| if (transaction) { |
| em.getTransaction().begin(); |
| } |
| final Query jpaQuery; |
| try { |
| if (namedQuery != null) { |
| jpaQuery = em.createNamedQuery(namedQuery); |
| } else { |
| jpaQuery = em.createQuery(query); |
| } |
| jpaQuery.setFirstResult(firstResult).setMaxResults(page); |
| if (paramProvider != null) { |
| paramProvider.getValue().setParameters(jpaQuery); |
| } |
| final List<?> resultList = jpaQuery.getResultList(); |
| if (detach) { |
| for (final Object o : resultList) { |
| em.detach(o); |
| } |
| } |
| return resultList; |
| } finally { |
| if (transaction) { |
| em.getTransaction().commit(); |
| } |
| emProvider.getValue().release(em); |
| } |
| } |
| |
| @Override |
| public Serializable checkpointInfo() throws Exception { |
| return null; |
| } |
| } |