001    // Copyright 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.listener;
016    
017    import org.apache.hivemind.util.Defense;
018    import org.apache.tapestry.IActionListener;
019    import org.apache.tapestry.IComponent;
020    import org.apache.tapestry.IRequestCycle;
021    
022    /**
023     * Adapter class that combines a target object (typically, a component) with a
024     * {@link org.apache.tapestry.listener.ListenerMethodInvoker}. This is the bridge from listener
025     * method names to listener method invocations.
026     * <p>
027     * TODO: It would really be nice if we could get the location of the listener binding into thrown
028     * exceptions. As implemented, as best, it will be the location of the &lt;page-specification&gt;
029     * (or &lt;component&gt;) of the page (or component) containing the listener method.
030     * 
031     * @author Howard M. Lewis Ship
032     * @since 4.0
033     */
034    public class SyntheticListener implements IActionListener
035    {
036        private final Object _target;
037    
038        private final ListenerMethodInvoker _invoker;
039    
040        public SyntheticListener(Object target, ListenerMethodInvoker invoker)
041        {
042            Defense.notNull(target, "target");
043            Defense.notNull(invoker, "invoker");
044    
045            _target = target;
046            _invoker = invoker;
047        }
048    
049        public void actionTriggered(IComponent component, IRequestCycle cycle)
050        {
051            _invoker.invokeListenerMethod(_target, cycle);
052        }
053    }