001    // Copyright 2009, 2010 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.json.JSONObject;
019    import org.apache.tapestry5.services.PartialMarkupRenderer;
020    
021    /**
022     * Terminator for the {@link org.apache.tapestry5.services.PartialMarkupRenderer} pipeline, which ultimately invokes
023     * {@link org.apache.tapestry5.internal.services.PageRenderQueue#renderPartial(org.apache.tapestry5.MarkupWriter, org.apache.tapestry5.json.JSONObject)}
024     * .
025     * 
026     * @since 5.1.0.0
027     */
028    public class PartialMarkupRendererTerminator implements PartialMarkupRenderer
029    {
030        private final PageRenderQueue renderQueue;
031    
032        public PartialMarkupRendererTerminator(PageRenderQueue renderQueue)
033        {
034            this.renderQueue = renderQueue;
035        }
036    
037        public void renderMarkup(MarkupWriter writer, JSONObject reply)
038        {
039            // Ensure that whatever renders will do so inside a root element.
040            // Omitting this causes NPEs when rendering individual zones
041            // of a MultiZoneUpdate
042    
043            writer.element("partial-render-root-element");
044    
045            renderQueue.renderPartial(writer, reply);
046    
047            writer.end();
048        }
049    }