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
015package org.apache.tapestry.components;
016
017import org.apache.tapestry.AbstractComponent;
018import org.apache.tapestry.IActionListener;
019import org.apache.tapestry.IMarkupWriter;
020import org.apache.tapestry.IRequestCycle;
021import org.apache.tapestry.link.DirectLink;
022import 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 */
031public 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}