/*
* Copyright 2004 The Apache Software Foundation
*
* 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 javax.servlet.http;

import java.util.EventListener;


/**
 * Causes an object to be notified when it is bound to
 * or unbound from a session. The object is notified
 * by an {@link HttpSessionBindingEvent} object. This may be as a result
 * of a servlet programmer explicitly unbinding an attribute from a session,
 * due to a session being invalidated, or due to a session timing out.
 *
 *
 * @author		Various
 * @version		$Version$
 *
 * @see HttpSession
 * @see HttpSessionBindingEvent
 *
 */

public interface HttpSessionBindingListener extends EventListener {


    /**
     *
     * Notifies the object that it is being bound to
     * a session and identifies the session.
     *
     * @param event		the event that identifies the
     *				session 
     *
     * @see #valueUnbound
     *
     */ 

    public void valueBound(HttpSessionBindingEvent event);
    
    
    /**
     *
     * Notifies the object that it is being unbound
     * from a session and identifies the session.
     *
     * @param event		the event that identifies
     *				the session 
     *	
     * @see #valueBound
     *
     */

    public void valueUnbound(HttpSessionBindingEvent event);
    
    
}