/*
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
* contributor license agreements. See the NOTICE file distributed with
|
* this work for additional information regarding copyright ownership.
|
* The ASF 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 listeners;
|
|
|
import javax.servlet.ServletContext;
|
import javax.servlet.ServletContextAttributeEvent;
|
import javax.servlet.ServletContextAttributeListener;
|
import javax.servlet.ServletContextEvent;
|
import javax.servlet.ServletContextListener;
|
|
|
/**
|
* Example listener for context-related application events, which were
|
* introduced in the 2.3 version of the Servlet API. This listener
|
* merely documents the occurrence of such events in the application log
|
* associated with our servlet context.
|
*
|
* @author Craig R. McClanahan
|
*/
|
public final class ContextListener
|
implements ServletContextAttributeListener, ServletContextListener {
|
|
|
// ----------------------------------------------------- Instance Variables
|
|
|
/**
|
* The servlet context with which we are associated.
|
*/
|
private ServletContext context = null;
|
|
|
// --------------------------------------------------------- Public Methods
|
|
|
/**
|
* Record the fact that a servlet context attribute was added.
|
*
|
* @param event The servlet context attribute event
|
*/
|
@Override
|
public void attributeAdded(ServletContextAttributeEvent event) {
|
|
log("attributeAdded('" + event.getName() + "', '" +
|
event.getValue() + "')");
|
|
}
|
|
|
/**
|
* Record the fact that a servlet context attribute was removed.
|
*
|
* @param event The servlet context attribute event
|
*/
|
@Override
|
public void attributeRemoved(ServletContextAttributeEvent event) {
|
|
log("attributeRemoved('" + event.getName() + "', '" +
|
event.getValue() + "')");
|
|
}
|
|
|
/**
|
* Record the fact that a servlet context attribute was replaced.
|
*
|
* @param event The servlet context attribute event
|
*/
|
@Override
|
public void attributeReplaced(ServletContextAttributeEvent event) {
|
|
log("attributeReplaced('" + event.getName() + "', '" +
|
event.getValue() + "')");
|
|
}
|
|
|
/**
|
* Record the fact that this web application has been destroyed.
|
*
|
* @param event The servlet context event
|
*/
|
@Override
|
public void contextDestroyed(ServletContextEvent event) {
|
|
log("contextDestroyed()");
|
this.context = null;
|
|
}
|
|
|
/**
|
* Record the fact that this web application has been initialized.
|
*
|
* @param event The servlet context event
|
*/
|
@Override
|
public void contextInitialized(ServletContextEvent event) {
|
|
this.context = event.getServletContext();
|
log("contextInitialized()");
|
|
}
|
|
|
// -------------------------------------------------------- Private Methods
|
|
|
/**
|
* Log a message to the servlet context application log.
|
*
|
* @param message Message to be logged
|
*/
|
private void log(String message) {
|
|
if (context != null) {
|
context.log("ContextListener: " + message);
|
} else {
|
System.out.println("ContextListener: " + message);
|
}
|
|
}
|
|
}
|
