001    // Copyright 2004, 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;
016    
017    /**
018     *  An element that may be asked to render itself to an
019     *  {@link IMarkupWriter} using a {@link IRequestCycle}.
020     *
021     *  <p>This primarily includes {@link IComponent} and {@link IPage},
022     *  but also extends to other things, such as objects responsible for
023     *  rendering static markup text.
024     *
025     *  @author Howard Lewis Ship
026     *
027     **/
028    
029    public interface IRender
030    {
031        /**
032         *  The principal rendering/rewinding method.  This will cause
033         *  the receiving component to render its top level elements (HTML
034         *  text and components).
035         *
036         *  <p>Renderring and rewinding are the exact same process.  The
037         *  same code that renders must be able to restore state by going
038         *  through the exact same operations (even though the output is
039         *  discarded).
040         *
041         **/
042    
043        void render(IMarkupWriter writer, IRequestCycle cycle);
044        
045    }