001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     * 
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     * 
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License. 
016     */
017    
018    package org.apache.commons.pipeline;
019    
020    import java.util.EventListener;
021    import java.util.EventObject;
022    
023    /**
024     * Listener interface for {@link EventObject}s. Listeners are notified of
025     * events by the {@link StageContext} with which they are registered.
026     */
027    public interface StageEventListener extends EventListener {
028        
029        /**
030         * Notify this listener of a {@link StageEvent}
031         * @param ev The event to be handled. Listeners should gracefully ignore any events that they
032         * do not know how to handle.
033         */
034        public abstract void notify(EventObject ev);
035    }