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.components;
016    
017    import org.apache.tapestry.AbstractComponent;
018    import org.apache.tapestry.IActionListener;
019    import org.apache.tapestry.IMarkupWriter;
020    import org.apache.tapestry.IRequestCycle;
021    import org.apache.tapestry.link.DirectLink;
022    import org.apache.tapestry.listener.ListenerInvoker;
023    
024    /**
025     * Invokes a listener method, passing listener parameters. This is used when a page or component
026     * needs some setup logic that can be best accomplished in Java code.
027     * 
028     * @author Howard M. Lewis Ship
029     * @since 4.0
030     */
031    public abstract class InvokeListener extends AbstractComponent
032    {
033        protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
034        {
035            Object[] parameters = DirectLink.constructServiceParameters(getParameters());
036    
037            try
038            {
039                cycle.setListenerParameters(parameters);
040    
041                getListenerInvoker().invokeListener(getListener(), this, cycle);
042            }
043            finally
044            {
045                cycle.setListenerParameters(null);
046            }
047        }
048    
049        /** Parameter */
050        public abstract IActionListener getListener();
051    
052        /** Parameter */
053        public abstract Object getParameters();
054    
055        /** Injected */
056        public abstract ListenerInvoker getListenerInvoker();
057    }