001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.orm.jpa.support;
018
019import javax.persistence.EntityManager;
020import javax.persistence.EntityManagerFactory;
021
022import org.springframework.beans.factory.FactoryBean;
023import org.springframework.beans.factory.InitializingBean;
024import org.springframework.lang.Nullable;
025import org.springframework.orm.jpa.EntityManagerFactoryAccessor;
026import org.springframework.orm.jpa.EntityManagerFactoryInfo;
027import org.springframework.orm.jpa.SharedEntityManagerCreator;
028import org.springframework.util.Assert;
029
030/**
031 * {@link FactoryBean} that exposes a shared JPA {@link javax.persistence.EntityManager}
032 * reference for a given EntityManagerFactory. Typically used for an EntityManagerFactory
033 * created by {@link org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean},
034 * as direct alternative to a JNDI lookup for a Java EE server's EntityManager reference.
035 *
036 * <p>The shared EntityManager will behave just like an EntityManager fetched from an
037 * application server's JNDI environment, as defined by the JPA specification.
038 * It will delegate all calls to the current transactional EntityManager, if any;
039 * otherwise, it will fall back to a newly created EntityManager per operation.
040 *
041 * <p>Can be passed to DAOs that expect a shared EntityManager reference rather than an
042 * EntityManagerFactory. Note that Spring's {@link org.springframework.orm.jpa.JpaTransactionManager}
043 * always needs an EntityManagerFactory in order to create new transactional EntityManager instances.
044 *
045 * @author Juergen Hoeller
046 * @since 2.0
047 * @see #setEntityManagerFactory
048 * @see #setEntityManagerInterface
049 * @see org.springframework.orm.jpa.LocalEntityManagerFactoryBean
050 * @see org.springframework.orm.jpa.JpaTransactionManager
051 */
052public class SharedEntityManagerBean extends EntityManagerFactoryAccessor
053                implements FactoryBean<EntityManager>, InitializingBean {
054
055        @Nullable
056        private Class<? extends EntityManager> entityManagerInterface;
057
058        private boolean synchronizedWithTransaction = true;
059
060        @Nullable
061        private EntityManager shared;
062
063
064        /**
065         * Specify the EntityManager interface to expose.
066         * <p>Default is the EntityManager interface as defined by the
067         * EntityManagerFactoryInfo, if available. Else, the standard
068         * {@code javax.persistence.EntityManager} interface will be used.
069         * @see org.springframework.orm.jpa.EntityManagerFactoryInfo#getEntityManagerInterface()
070         * @see javax.persistence.EntityManager
071         */
072        public void setEntityManagerInterface(Class<? extends EntityManager> entityManagerInterface) {
073                Assert.notNull(entityManagerInterface, "'entityManagerInterface' must not be null");
074                this.entityManagerInterface = entityManagerInterface;
075        }
076
077        /**
078         * Set whether to automatically join ongoing transactions (according
079         * to the JPA 2.1 SynchronizationType rules). Default is "true".
080         */
081        public void setSynchronizedWithTransaction(boolean synchronizedWithTransaction) {
082                this.synchronizedWithTransaction = synchronizedWithTransaction;
083        }
084
085
086        @Override
087        public final void afterPropertiesSet() {
088                EntityManagerFactory emf = getEntityManagerFactory();
089                if (emf == null) {
090                        throw new IllegalArgumentException("'entityManagerFactory' or 'persistenceUnitName' is required");
091                }
092                if (emf instanceof EntityManagerFactoryInfo) {
093                        EntityManagerFactoryInfo emfInfo = (EntityManagerFactoryInfo) emf;
094                        if (this.entityManagerInterface == null) {
095                                this.entityManagerInterface = emfInfo.getEntityManagerInterface();
096                                if (this.entityManagerInterface == null) {
097                                        this.entityManagerInterface = EntityManager.class;
098                                }
099                        }
100                }
101                else {
102                        if (this.entityManagerInterface == null) {
103                                this.entityManagerInterface = EntityManager.class;
104                        }
105                }
106                this.shared = SharedEntityManagerCreator.createSharedEntityManager(
107                                emf, getJpaPropertyMap(), this.synchronizedWithTransaction, this.entityManagerInterface);
108        }
109
110
111        @Override
112        @Nullable
113        public EntityManager getObject() {
114                return this.shared;
115        }
116
117        @Override
118        public Class<? extends EntityManager> getObjectType() {
119                return (this.entityManagerInterface != null ? this.entityManagerInterface : EntityManager.class);
120        }
121
122        @Override
123        public boolean isSingleton() {
124                return true;
125        }
126
127}