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.event;
016    
017    import java.util.EventListener;
018    
019    /**
020     * Event listener for determining when a page is about to start rendering.
021     * Rendering includes the replay of a form to handle form submissions.
022     * 
023     * @author Howard M. Lewis Ship
024     * @since 4.0
025     */
026    public interface PageBeginRenderListener extends EventListener
027    {
028    
029        /**
030         * Invoked before just before the page renders a response. This provides
031         * listeners with a last chance to initialize themselves for the render.
032         * This initialization can include modifying peristent page properties.
033         */
034    
035        void pageBeginRender(PageEvent event);
036    }