org.springframework.orm.hibernate.support.OpenSessionInViewInterceptor Maven / Gradle / Ivy
/*
* 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.hibernate.support;
import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Session;
import org.springframework.dao.DataAccessException;
import org.springframework.orm.hibernate.HibernateAccessor;
import org.springframework.orm.hibernate.SessionFactoryUtils;
import org.springframework.orm.hibernate.SessionHolder;
import org.springframework.transaction.support.TransactionSynchronizationManager;
import org.springframework.ui.ModelMap;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.context.request.WebRequestInterceptor;
/**
* Spring web request interceptor that binds a Hibernate Session to the thread for the
* entire processing of the request. Intended for the "Open Session in View" pattern,
* that is, to allow for lazy loading in web views despite the original transactions
* already being completed.
*
* This interceptor makes Hibernate Sessions available via the current thread,
* which will be autodetected by transaction managers. It is suitable for service layer
* transactions via {@link org.springframework.orm.hibernate.HibernateTransactionManager}
* or {@link org.springframework.transaction.jta.JtaTransactionManager} as well
* as for non-transactional execution (if configured appropriately).
*
*
NOTE: This interceptor will by default not flush the Hibernate Session,
* with the flush mode set to FlushMode.NEVER. It assumes to be used
* in combination with service layer transactions that care for the flushing: The
* active transaction manager will temporarily change the flush mode to
* FlushMode.AUTO during a read-write transaction, with the flush
* mode reset to FlushMode.NEVER at the end of each transaction.
* If you intend to use this interceptor without transactions, consider changing
* the default flush mode (through the "flushMode" property).
*
*
In contrast to {@link OpenSessionInViewFilter}, this interceptor is set up
* in a Spring application context and can thus take advantage of bean wiring.
* It inherits common Hibernate configuration properties from
* {@link org.springframework.orm.hibernate.HibernateAccessor},
* to be configured in a bean definition.
*
*
WARNING: Applying this interceptor to existing logic can cause issues that
* have not appeared before, through the use of a single Hibernate Session for the
* processing of an entire request. In particular, the reassociation of persistent
* objects with a Hibernate Session has to occur at the very beginning of request
* processing, to avoid clashes will already loaded instances of the same objects.
*
*
Alternatively, turn this interceptor into deferred close mode, by specifying
* "singleSession"="false": It will not use a single session per request then,
* but rather let each data access operation or transaction use its own session
* (like without Open Session in View). Each of those sessions will be registered
* for deferred close, though, actually processed at request completion.
*
*
A single session per request allows for most efficient first-level caching,
* but can cause side effects, for example on saveOrUpdate or when
* continuing after a rolled-back transaction. The deferred close strategy is as safe
* as no Open Session in View in that respect, while still allowing for lazy loading
* in views (but not providing a first-level cache for the entire request).
*
* @author Juergen Hoeller
* @since 06.12.2003
* @see #setSingleSession
* @see #setFlushMode
* @see OpenSessionInViewFilter
* @see org.springframework.orm.hibernate.HibernateInterceptor
* @see org.springframework.orm.hibernate.HibernateTransactionManager
* @see org.springframework.orm.hibernate.SessionFactoryUtils#getSession
* @see org.springframework.transaction.support.TransactionSynchronizationManager
*/
public class OpenSessionInViewInterceptor extends HibernateAccessor implements WebRequestInterceptor {
/**
* Suffix that gets appended to the SessionFactory toString representation
* for the "participate in existing session handling" request attribute.
* @see #getParticipateAttributeName
*/
public static final String PARTICIPATE_SUFFIX = ".PARTICIPATE";
private boolean singleSession = true;
/**
* Create a new OpenSessionInViewInterceptor,
* turning the default flushMode to FLUSH_NEVER.
* @see #setFlushMode
*/
public OpenSessionInViewInterceptor() {
setFlushMode(FLUSH_NEVER);
}
/**
* Set whether to use a single session for each request. Default is "true".
*
If set to false, each data access operation or transaction will use
* its own session (like without Open Session in View). Each of those
* sessions will be registered for deferred close, though, actually
* processed at request completion.
* @see SessionFactoryUtils#initDeferredClose
* @see SessionFactoryUtils#processDeferredClose
*/
public void setSingleSession(boolean singleSession) {
this.singleSession = singleSession;
}
/**
* Return whether to use a single session for each request.
*/
protected boolean isSingleSession() {
return singleSession;
}
/**
* Open a new Hibernate Session according to the settings of this HibernateAccessor
* and binds in to the thread via TransactionSynchronizationManager.
* @see org.springframework.orm.hibernate.SessionFactoryUtils#getSession
* @see org.springframework.transaction.support.TransactionSynchronizationManager
*/
public void preHandle(WebRequest request) throws DataAccessException {
if ((isSingleSession() && TransactionSynchronizationManager.hasResource(getSessionFactory())) ||
SessionFactoryUtils.isDeferredCloseActive(getSessionFactory())) {
// Do not modify the Session: just mark the request accordingly.
String participateAttributeName = getParticipateAttributeName();
Integer count = (Integer) request.getAttribute(participateAttributeName, WebRequest.SCOPE_REQUEST);
int newCount = (count != null) ? count.intValue() + 1 : 1;
request.setAttribute(getParticipateAttributeName(), new Integer(newCount), WebRequest.SCOPE_REQUEST);
}
else {
if (isSingleSession()) {
// single session mode
logger.debug("Opening single Hibernate Session in OpenSessionInViewInterceptor");
Session session = SessionFactoryUtils.getSession(
getSessionFactory(), getEntityInterceptor(), getJdbcExceptionTranslator());
applyFlushMode(session, false);
TransactionSynchronizationManager.bindResource(getSessionFactory(), new SessionHolder(session));
}
else {
// deferred close mode
SessionFactoryUtils.initDeferredClose(getSessionFactory());
}
}
}
/**
* Flush the Hibernate Session before view rendering, if necessary.
* Note that this just applies in single session mode!
*
The default is FLUSH_NEVER to avoid this extra flushing, assuming that
* service layer transactions have flushed their changes on commit.
* @see #setFlushMode
*/
public void postHandle(WebRequest request, ModelMap model) throws DataAccessException {
if (isSingleSession()) {
// Only potentially flush in single session mode.
SessionHolder sessionHolder =
(SessionHolder) TransactionSynchronizationManager.getResource(getSessionFactory());
logger.debug("Flushing single Hibernate Session in OpenSessionInViewInterceptor");
try {
flushIfNecessary(sessionHolder.getSession(), false);
}
catch (HibernateException ex) {
throw convertHibernateAccessException(ex);
}
}
}
/**
* Unbind the Hibernate Session from the thread and closes it (in single session
* mode), or process deferred close for all sessions that have been opened
* during the current request (in deferred close mode).
* @see org.springframework.transaction.support.TransactionSynchronizationManager
*/
public void afterCompletion(WebRequest request, Exception ex) throws DataAccessException {
String participateAttributeName = getParticipateAttributeName();
Integer count = (Integer) request.getAttribute(participateAttributeName, WebRequest.SCOPE_REQUEST);
if (count != null) {
// Do not modify the Session: just clear the marker.
if (count.intValue() > 1) {
request.setAttribute(participateAttributeName, new Integer(count.intValue() - 1), WebRequest.SCOPE_REQUEST);
}
else {
request.removeAttribute(participateAttributeName, WebRequest.SCOPE_REQUEST);
}
}
else {
if (isSingleSession()) {
// single session mode
SessionHolder sessionHolder =
(SessionHolder) TransactionSynchronizationManager.unbindResource(getSessionFactory());
logger.debug("Closing single Hibernate Session in OpenSessionInViewInterceptor");
SessionFactoryUtils.closeSession(sessionHolder.getSession());
}
else {
// deferred close mode
SessionFactoryUtils.processDeferredClose(getSessionFactory());
}
}
}
/**
* Return the name of the request attribute that identifies that a request is
* already intercepted. Default implementation takes the toString representation
* of the SessionFactory instance and appends ".PARTICIPATE".
* @see #PARTICIPATE_SUFFIX
*/
protected String getParticipateAttributeName() {
return getSessionFactory().toString() + PARTICIPATE_SUFFIX;
}
}