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
015package org.apache.tapestry5.internal.services;
016
017import org.apache.tapestry5.MarkupWriter;
018import org.apache.tapestry5.json.JSONObject;
019import 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 */
028public 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}