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Spring Framework example source code file (OpenPersistenceManagerInViewFilter.java)

This example Spring Framework source code file (OpenPersistenceManagerInViewFilter.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

default_persistence_manager_factory_bean_name, filterchain, http, io, ioexception, jdo, opening, openpersistencemanagerinviewfilter, openpersistencemanagerinviewfilter, persistencemanager, persistencemanager, persistencemanagerfactory, persistencemanagerfactory, persistencemanagerholder, request, response, servlet, string, string

The Spring Framework OpenPersistenceManagerInViewFilter.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.jdo.support;

import java.io.IOException;

import javax.jdo.PersistenceManager;
import javax.jdo.PersistenceManagerFactory;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.orm.jdo.PersistenceManagerFactoryUtils;
import org.springframework.orm.jdo.PersistenceManagerHolder;
import org.springframework.transaction.support.TransactionSynchronizationManager;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.filter.OncePerRequestFilter;

/**
 * Servlet 2.3 Filter that binds a JDO PersistenceManager to the thread for the
 * entire processing of the request. Intended for the "Open PersistenceManager in
 * View" pattern, i.e. to allow for lazy loading in web views despite the
 * original transactions already being completed.
 *
 * <p>This filter makes JDO PersistenceManagers available via the current thread,
 * which will be autodetected by transaction managers. It is suitable for service
 * layer transactions via {@link org.springframework.orm.jdo.JdoTransactionManager}
 * or {@link org.springframework.transaction.jta.JtaTransactionManager} as well
 * as for non-transactional read-only execution.
 *
 * <p>Looks up the PersistenceManagerFactory in Spring's root web application context.
 * Supports a "persistenceManagerFactoryBeanName" filter init-param in <code>web.xml;
 * the default bean name is "persistenceManagerFactory". Looks up the PersistenceManagerFactory
 * on each request, to avoid initialization order issues (when using ContextLoaderServlet,
 * the root application context will get initialized <i>after this filter).
 *
 * @author Juergen Hoeller
 * @since 1.1
 * @see OpenPersistenceManagerInViewInterceptor
 * @see org.springframework.orm.jdo.JdoInterceptor
 * @see org.springframework.orm.jdo.JdoTransactionManager
 * @see org.springframework.orm.jdo.PersistenceManagerFactoryUtils#getPersistenceManager
 * @see org.springframework.transaction.support.TransactionSynchronizationManager
 */
public class OpenPersistenceManagerInViewFilter extends OncePerRequestFilter {

	public static final String DEFAULT_PERSISTENCE_MANAGER_FACTORY_BEAN_NAME = "persistenceManagerFactory";

	private String persistenceManagerFactoryBeanName = DEFAULT_PERSISTENCE_MANAGER_FACTORY_BEAN_NAME;


	/**
	 * Set the bean name of the PersistenceManagerFactory to fetch from Spring's
	 * root application context. Default is "persistenceManagerFactory".
	 * @see #DEFAULT_PERSISTENCE_MANAGER_FACTORY_BEAN_NAME
	 */
	public void setPersistenceManagerFactoryBeanName(String persistenceManagerFactoryBeanName) {
		this.persistenceManagerFactoryBeanName = persistenceManagerFactoryBeanName;
	}

	/**
	 * Return the bean name of the PersistenceManagerFactory to fetch from Spring's
	 * root application context.
	 */
	protected String getPersistenceManagerFactoryBeanName() {
		return this.persistenceManagerFactoryBeanName;
	}


	protected void doFilterInternal(
			HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {

		PersistenceManagerFactory pmf = lookupPersistenceManagerFactory(request);
		boolean participate = false;

		if (TransactionSynchronizationManager.hasResource(pmf)) {
			// Do not modify the PersistenceManager: just set the participate flag.
			participate = true;
		}
		else {
			logger.debug("Opening JDO PersistenceManager in OpenPersistenceManagerInViewFilter");
			PersistenceManager pm = PersistenceManagerFactoryUtils.getPersistenceManager(pmf, true);
			TransactionSynchronizationManager.bindResource(pmf, new PersistenceManagerHolder(pm));
		}

		try {
			filterChain.doFilter(request, response);
		}

		finally {
			if (!participate) {
				PersistenceManagerHolder pmHolder = (PersistenceManagerHolder)
						TransactionSynchronizationManager.unbindResource(pmf);
				logger.debug("Closing JDO PersistenceManager in OpenPersistenceManagerInViewFilter");
				PersistenceManagerFactoryUtils.releasePersistenceManager(pmHolder.getPersistenceManager(), pmf);
			}
		}
	}

	/**
	 * Look up the PersistenceManagerFactory that this filter should use,
	 * taking the current HTTP request as argument.
	 * <p>Default implementation delegates to the lookupPersistenceManagerFactory
	 * without arguments.
	 * @return the PersistenceManagerFactory to use
	 * @see #lookupPersistenceManagerFactory()
	 */
	protected PersistenceManagerFactory lookupPersistenceManagerFactory(HttpServletRequest request) {
		return lookupPersistenceManagerFactory();
	}

	/**
	 * Look up the PersistenceManagerFactory that this filter should use.
	 * The default implementation looks for a bean with the specified name
	 * in Spring's root application context.
	 * @return the PersistenceManagerFactory to use
	 * @see #getPersistenceManagerFactoryBeanName
	 */
	protected PersistenceManagerFactory lookupPersistenceManagerFactory() {
		if (logger.isDebugEnabled()) {
			logger.debug("Using PersistenceManagerFactory '" + getPersistenceManagerFactoryBeanName() +
					"' for OpenPersistenceManagerInViewFilter");
		}
		WebApplicationContext wac =
				WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
		return (PersistenceManagerFactory)
				wac.getBean(getPersistenceManagerFactoryBeanName(), PersistenceManagerFactory.class);
	}

}

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