/**
* Licensed to Jasig under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Jasig licenses this file to you 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.jasig.portal.utils.web;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import org.jasig.portal.utils.SerializableObject;
/**
* Servlet 2.3 HttpSessionListener that automatically exposes the
* request attribute mutex when an ServletRequest gets created.
* To be registered as a listener in <code>web.xml</code>.
*
* <p>The request attribute mutex is guaranteed to be the same object during
* the entire lifetime of the request, available under the key defined
* by the <code>REQUEST_MUTEX_ATTRIBUTE</code> constant. It serves as a
* safe reference to synchronize on for locking on the current request attributes.
*
* @author Eric Dalquist
* @version $Revision$
*/
public class RequestAttributeMutexListener implements ServletRequestListener {
/* (non-Javadoc)
* @see javax.servlet.ServletRequestListener#requestInitialized(javax.servlet.ServletRequestEvent)
*/
@Override
public void requestInitialized(ServletRequestEvent sre) {
sre.getServletRequest().setAttribute(PortalWebUtils.REQUEST_MUTEX_ATTRIBUTE, new SerializableObject());
}
/* (non-Javadoc)
* @see javax.servlet.ServletRequestListener#requestDestroyed(javax.servlet.ServletRequestEvent)
*/
@Override
public void requestDestroyed(ServletRequestEvent sre) {
sre.getServletRequest().removeAttribute(PortalWebUtils.REQUEST_MUTEX_ATTRIBUTE);
}
}