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    package javax.servlet;
021    
022    import java.util.EventListener;
023    
024            /** Implementations of this interface receive notifications of
025            ** changes to the attribute list on the servlet context of a web application. 
026            * To receive notification events, the implementation class
027            * must be configured in the deployment descriptor for the web application.
028            * @see ServletContextAttributeEvent
029             * @since       v 2.3
030            */
031    
032    public interface ServletContextAttributeListener extends EventListener {
033            /** Notification that a new attribute was added to the servlet context. Called after the attribute is added.*/
034    public void attributeAdded(ServletContextAttributeEvent scab);
035            /** Notification that an existing attribute has been removed from the servlet context. Called after the attribute is removed.*/
036    public void attributeRemoved(ServletContextAttributeEvent scab);
037            /** Notification that an attribute on the servlet context has been replaced. Called after the attribute is replaced. */
038    public void attributeReplaced(ServletContextAttributeEvent scab);
039    }
040