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Spring Framework example source code file (JpaAccessor.java)

This example Spring Framework source code file (JpaAccessor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Spring Framework tags/keywords

defaultjpadialect, defaultjpadialect, entitymanager, entitymanager, entitymanagerfactory, entitymanagerfactoryaccessor, entitymanagerfactoryinfo, entitymanagerfactoryinfo, illegalargumentexception, jpaaccessor, jpadialect, jpadialect, persistenceexception, runtimeexception

The Spring Framework JpaAccessor.java source code

/*
 * Copyright 2002-2007 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.orm.jpa;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceException;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.dao.support.DataAccessUtils;

/**
 * Base class for JpaTemplate and JpaInterceptor, defining common
 * properties such as EntityManagerFactory and flushing behavior.
 *
 * <p>Not intended to be used directly.
 * See {@link JpaTemplate} and {@link JpaInterceptor}.
 *
 * @author Juergen Hoeller
 * @since 2.0
 * @see #setEntityManagerFactory
 * @see #setEntityManager
 * @see #setJpaDialect
 * @see #setFlushEager
 * @see JpaTemplate
 * @see JpaInterceptor
 * @see JpaDialect
 */
public abstract class JpaAccessor extends EntityManagerFactoryAccessor implements InitializingBean {

	private EntityManager entityManager;

	private JpaDialect jpaDialect = new DefaultJpaDialect();

	private boolean flushEager = false;


	/**
	 * Set the JPA EntityManager to use.
	 */
	public void setEntityManager(EntityManager entityManager) {
		this.entityManager = entityManager;
	}

	/**
	 * Return the JPA EntityManager to use.
	 */
	public EntityManager getEntityManager() {
		return entityManager;
	}

	/**
	 * Set the JPA dialect to use for this accessor.
	 * <p>The dialect object can be used to retrieve the underlying JDBC
	 * connection, for example.
	 */
	public void setJpaDialect(JpaDialect jpaDialect) {
		this.jpaDialect = (jpaDialect != null ? jpaDialect : new DefaultJpaDialect());
	}

	/**
	 * Return the JPA dialect to use for this accessor.
	 * <p>Creates a default one for the specified EntityManagerFactory if none set.
	 */
	public JpaDialect getJpaDialect() {
		return this.jpaDialect;
	}

	/**
	 * Set if this accessor should flush changes to the database eagerly.
	 * <p>Eager flushing leads to immediate synchronization with the database,
	 * even if in a transaction. This causes inconsistencies to show up and throw
	 * a respective exception immediately, and JDBC access code that participates
	 * in the same transaction will see the changes as the database is already
	 * aware of them then. But the drawbacks are:
	 * <ul>
	 * <li>additional communication roundtrips with the database, instead of a
	 * single batch at transaction commit;
	 * <li>the fact that an actual database rollback is needed if the JPA
	 * transaction rolls back (due to already submitted SQL statements).
	 * </ul>
	 */
	public void setFlushEager(boolean flushEager) {
		this.flushEager = flushEager;
	}

	/**
	 * Return if this accessor should flush changes to the database eagerly.
	 */
	public boolean isFlushEager() {
		return this.flushEager;
	}

	/**
	 * Eagerly initialize the JPA dialect, creating a default one
	 * for the specified EntityManagerFactory if none set.
	 */
	public void afterPropertiesSet() {
		EntityManagerFactory emf = getEntityManagerFactory();
		if (emf == null && getEntityManager() == null) {
			throw new IllegalArgumentException("entityManagerFactory or entityManager is required");
		}
		if (emf instanceof EntityManagerFactoryInfo) {
			JpaDialect jpaDialect = ((EntityManagerFactoryInfo) emf).getJpaDialect();
			if (jpaDialect != null) {
				setJpaDialect(jpaDialect);
			}
		}
	}


	/**
	 * Flush the given JPA entity manager if necessary.
	 * @param em the current JPA PersistenceManage
	 * @param existingTransaction if executing within an existing transaction
	 * @throws javax.persistence.PersistenceException in case of JPA flushing errors
	 */
	protected void flushIfNecessary(EntityManager em, boolean existingTransaction) throws PersistenceException {
		if (isFlushEager()) {
			logger.debug("Eagerly flushing JPA entity manager");
			em.flush();
		}
	}

	/**
	 * Convert the given runtime exception to an appropriate exception from the
	 * <code>org.springframework.dao hierarchy if necessary, or
	 * return the exception itself if it is not persistence related
	 * <p>Default implementation delegates to the JpaDialect.
	 * May be overridden in subclasses.
	 * @param ex runtime exception that occured, which may or may not
	 * be JPA-related
	 * @return the corresponding DataAccessException instance if
	 * wrapping should occur, otherwise the raw exception
	 * @see org.springframework.dao.support.DataAccessUtils#translateIfNecessary
	 */
	public RuntimeException translateIfNecessary(RuntimeException ex) {
		return DataAccessUtils.translateIfNecessary(ex, getJpaDialect());
	}

}

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