/*
 * 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.
 */

//
// This source code implements specifications defined by the Java
// Community Process. In order to remain compliant with the specification
// DO NOT add / change / or delete method signatures!
//

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.
 *
 * @see HttpSession
 * @see HttpSessionBindingEvent
 *
 * @version $Rev$ $Date$
 */
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);
}