001    // Copyright 2007, 2008, 2010, 2011 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.tapestry5.internal.services;
016    
017    import org.apache.tapestry5.MarkupWriter;
018    import org.apache.tapestry5.dom.Element;
019    import org.apache.tapestry5.internal.services.ajax.AjaxFormUpdateController;
020    import org.apache.tapestry5.json.JSONObject;
021    import org.apache.tapestry5.runtime.RenderCommand;
022    import org.apache.tapestry5.services.ComponentEventResultProcessor;
023    import org.apache.tapestry5.services.PartialMarkupRenderer;
024    import org.apache.tapestry5.services.PartialMarkupRendererFilter;
025    
026    import java.io.IOException;
027    
028    /**
029     * Processor for objects that implement {@link RenderCommand} (such as
030     * {@link org.apache.tapestry5.internal.structure.BlockImpl}), used with an Ajax component event.
031     *
032     * @see AjaxPartialResponseRenderer#renderPartialPageMarkup()
033     */
034    public class RenderCommandComponentEventResultProcessor implements ComponentEventResultProcessor<RenderCommand>,
035            PartialMarkupRendererFilter
036    {
037        private final PageRenderQueue pageRenderQueue;
038    
039        private final AjaxFormUpdateController ajaxFormUpdateController;
040    
041        private final AjaxPartialResponseRenderer partialRenderer;
042    
043        public RenderCommandComponentEventResultProcessor(PageRenderQueue pageRenderQueue,
044                                                          AjaxFormUpdateController ajaxFormUpdateController, AjaxPartialResponseRenderer partialRenderer)
045        {
046            this.pageRenderQueue = pageRenderQueue;
047            this.ajaxFormUpdateController = ajaxFormUpdateController;
048            this.partialRenderer = partialRenderer;
049        }
050    
051        public void processResultValue(RenderCommand value) throws IOException
052        {
053            pageRenderQueue.addPartialMarkupRendererFilter(this);
054            pageRenderQueue.addPartialRenderer(value);
055    
056            // And render the content right now.
057    
058            partialRenderer.renderPartialPageMarkup();
059        }
060    
061        /**
062         * As a filter, this class does three things:
063         * <ul>
064         * <li>It creates an outer element to capture the partial page content that will be rendered</li>
065         * <li>It does setup and cleanup with the {@link AjaxFormUpdateController}</li>
066         * <li>It extracts the child markup and stuffs it into the reply's "content" property.</li>
067         * </ul>
068         */
069        public void renderMarkup(MarkupWriter writer, JSONObject reply, PartialMarkupRenderer renderer)
070        {
071            // The partial will quite often contain multiple elements (or just a block of plain text),
072            // so those must be enclosed in a root element.
073    
074            Element root = writer.element("ajax-partial");
075    
076            ajaxFormUpdateController.setupBeforePartialZoneRender(writer);
077    
078            renderer.renderMarkup(writer, reply);
079    
080            ajaxFormUpdateController.cleanupAfterPartialZoneRender();
081    
082            writer.end();
083    
084            String content = root.getChildMarkup().trim();
085    
086            reply.put("content", content);
087        }
088    }