001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *  http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    
020    //
021    // This source code implements specifications defined by the Java
022    // Community Process. In order to remain compliant with the specification
023    // DO NOT add / change / or delete method signatures!
024    //
025    
026    package javax.servlet.http;
027    
028    import java.util.EventListener;
029    
030    /**
031     * Causes an object to be notified when it is bound to
032     * or unbound from a session. The object is notified
033     * by an {@link HttpSessionBindingEvent} object. This may be as a result
034     * of a servlet programmer explicitly unbinding an attribute from a session,
035     * due to a session being invalidated, or due to a session timing out.
036     *
037     * @see HttpSession
038     * @see HttpSessionBindingEvent
039     *
040     * @version $Rev: 467553 $ $Date: 2006-10-24 21:01:51 -0700 (Tue, 24 Oct 2006) $
041     */
042    public interface HttpSessionBindingListener extends EventListener {
043        /**
044         * Notifies the object that it is being bound to a session and identifies
045         * the session.
046         *
047         * @param event the event that identifies the session
048         *
049         * @see #valueUnbound
050         */
051        public void valueBound(HttpSessionBindingEvent event);
052    
053        /**
054         * Notifies the object that it is being unbound from a session and
055         * identifies the session.
056         *
057         * @param event the event that identifies the session
058         *
059         * @see #valueBound
060         */
061        public void valueUnbound(HttpSessionBindingEvent event);
062    }
063