/*
* Copyright 2002-2015 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.support;
import java.io.IOException;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceException;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.orm.jpa.EntityManagerFactoryUtils;
import org.springframework.orm.jpa.EntityManagerHolder;
import org.springframework.transaction.support.TransactionSynchronizationManager;
import org.springframework.util.StringUtils;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.async.WebAsyncManager;
import org.springframework.web.context.request.async.WebAsyncUtils;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.filter.OncePerRequestFilter;
/**
* Servlet Filter that binds a JPA EntityManager to the thread for the
* entire processing of the request. Intended for the "Open EntityManager in
* View" pattern, i.e. to allow for lazy loading in web views despite the
* original transactions already being completed.
*
* <p>This filter makes JPA EntityManagers available via the current thread,
* which will be autodetected by transaction managers. It is suitable for service
* layer transactions via {@link org.springframework.orm.jpa.JpaTransactionManager}
* or {@link org.springframework.transaction.jta.JtaTransactionManager} as well
* as for non-transactional read-only execution.
*
* <p>Looks up the EntityManagerFactory in Spring's root web application context.
* Supports an "entityManagerFactoryBeanName" filter init-param in {@code web.xml};
* the default bean name is "entityManagerFactory". As an alternative, the
* "persistenceUnitName" init-param allows for retrieval by logical unit name
* (as specified in {@code persistence.xml}).
*
* @author Juergen Hoeller
* @since 2.0
* @see OpenEntityManagerInViewInterceptor
* @see org.springframework.orm.jpa.JpaTransactionManager
* @see org.springframework.orm.jpa.SharedEntityManagerCreator
* @see org.springframework.transaction.support.TransactionSynchronizationManager
*/
public class OpenEntityManagerInViewFilter extends OncePerRequestFilter {
/**
* Default EntityManagerFactory bean name: "entityManagerFactory".
* Only applies when no "persistenceUnitName" param has been specified.
* @see #setEntityManagerFactoryBeanName
* @see #setPersistenceUnitName
*/
public static final String DEFAULT_ENTITY_MANAGER_FACTORY_BEAN_NAME = "entityManagerFactory";
private String entityManagerFactoryBeanName;
private String persistenceUnitName;
private volatile EntityManagerFactory entityManagerFactory;
/**
* Set the bean name of the EntityManagerFactory to fetch from Spring's
* root application context.
* <p>Default is "entityManagerFactory". Note that this default only applies
* when no "persistenceUnitName" param has been specified.
* @see #setPersistenceUnitName
* @see #DEFAULT_ENTITY_MANAGER_FACTORY_BEAN_NAME
*/
public void setEntityManagerFactoryBeanName(String entityManagerFactoryBeanName) {
this.entityManagerFactoryBeanName = entityManagerFactoryBeanName;
}
/**
* Return the bean name of the EntityManagerFactory to fetch from Spring's
* root application context.
*/
protected String getEntityManagerFactoryBeanName() {
return this.entityManagerFactoryBeanName;
}
/**
* Set the name of the persistence unit to access the EntityManagerFactory for.
* <p>This is an alternative to specifying the EntityManagerFactory by bean name,
* resolving it by its persistence unit name instead. If no bean name and no persistence
* unit name have been specified, we'll check whether a bean exists for the default
* bean name "entityManagerFactory"; if not, a default EntityManagerFactory will
* be retrieved through finding a single unique bean of type EntityManagerFactory.
* @see #setEntityManagerFactoryBeanName
* @see #DEFAULT_ENTITY_MANAGER_FACTORY_BEAN_NAME
*/
public void setPersistenceUnitName(String persistenceUnitName) {
this.persistenceUnitName = persistenceUnitName;
}
/**
* Return the name of the persistence unit to access the EntityManagerFactory for, if any.
*/
protected String getPersistenceUnitName() {
return this.persistenceUnitName;
}
/**
* Returns "false" so that the filter may re-bind the opened {@code EntityManager}
* to each asynchronously dispatched thread and postpone closing it until the very
* last asynchronous dispatch.
*/
@Override
protected boolean shouldNotFilterAsyncDispatch() {
return false;
}
/**
* Returns "false" so that the filter may provide an {@code EntityManager}
* to each error dispatches.
*/
@Override
protected boolean shouldNotFilterErrorDispatch() {
return false;
}
@Override
protected void doFilterInternal(
HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
EntityManagerFactory emf = lookupEntityManagerFactory(request);
boolean participate = false;
WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
String key = getAlreadyFilteredAttributeName();
if (TransactionSynchronizationManager.hasResource(emf)) {
// Do not modify the EntityManager: just set the participate flag.
participate = true;
}
else {
boolean isFirstRequest = !isAsyncDispatch(request);
if (isFirstRequest || !applyEntityManagerBindingInterceptor(asyncManager, key)) {
logger.debug("Opening JPA EntityManager in OpenEntityManagerInViewFilter");
try {
EntityManager em = createEntityManager(emf);
EntityManagerHolder emHolder = new EntityManagerHolder(em);
TransactionSynchronizationManager.bindResource(emf, emHolder);
AsyncRequestInterceptor interceptor = new AsyncRequestInterceptor(emf, emHolder);
asyncManager.registerCallableInterceptor(key, interceptor);
asyncManager.registerDeferredResultInterceptor(key, interceptor);
}
catch (PersistenceException ex) {
throw new DataAccessResourceFailureException("Could not create JPA EntityManager", ex);
}
}
}
try {
filterChain.doFilter(request, response);
}
finally {
if (!participate) {
EntityManagerHolder emHolder = (EntityManagerHolder)
TransactionSynchronizationManager.unbindResource(emf);
if (!isAsyncStarted(request)) {
logger.debug("Closing JPA EntityManager in OpenEntityManagerInViewFilter");
EntityManagerFactoryUtils.closeEntityManager(emHolder.getEntityManager());
}
}
}
}
/**
* Look up the EntityManagerFactory that this filter should use,
* taking the current HTTP request as argument.
* <p>The default implementation delegates to the {@code lookupEntityManagerFactory}
* without arguments, caching the EntityManagerFactory reference once obtained.
* @return the EntityManagerFactory to use
* @see #lookupEntityManagerFactory()
*/
protected EntityManagerFactory lookupEntityManagerFactory(HttpServletRequest request) {
if (this.entityManagerFactory == null) {
this.entityManagerFactory = lookupEntityManagerFactory();
}
return this.entityManagerFactory;
}
/**
* Look up the EntityManagerFactory that this filter should use.
* <p>The default implementation looks for a bean with the specified name
* in Spring's root application context.
* @return the EntityManagerFactory to use
* @see #getEntityManagerFactoryBeanName
*/
protected EntityManagerFactory lookupEntityManagerFactory() {
WebApplicationContext wac = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
String emfBeanName = getEntityManagerFactoryBeanName();
String puName = getPersistenceUnitName();
if (StringUtils.hasLength(emfBeanName)) {
return wac.getBean(emfBeanName, EntityManagerFactory.class);
}
else if (!StringUtils.hasLength(puName) && wac.containsBean(DEFAULT_ENTITY_MANAGER_FACTORY_BEAN_NAME)) {
return wac.getBean(DEFAULT_ENTITY_MANAGER_FACTORY_BEAN_NAME, EntityManagerFactory.class);
}
else {
// Includes fallback search for single EntityManagerFactory bean by type.
return EntityManagerFactoryUtils.findEntityManagerFactory(wac, puName);
}
}
/**
* Create a JPA EntityManager to be bound to a request.
* <p>Can be overridden in subclasses.
* @param emf the EntityManagerFactory to use
* @see javax.persistence.EntityManagerFactory#createEntityManager()
*/
protected EntityManager createEntityManager(EntityManagerFactory emf) {
return emf.createEntityManager();
}
private boolean applyEntityManagerBindingInterceptor(WebAsyncManager asyncManager, String key) {
if (asyncManager.getCallableInterceptor(key) == null) {
return false;
}
((AsyncRequestInterceptor) asyncManager.getCallableInterceptor(key)).bindSession();
return true;
}
}