001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005// http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.internal.services;
014
015import org.apache.tapestry5.MarkupWriter;
016import org.apache.tapestry5.commons.util.CollectionFactory;
017import org.apache.tapestry5.commons.util.Stack;
018import org.apache.tapestry5.internal.structure.Page;
019import org.apache.tapestry5.ioc.LoggerSource;
020import org.apache.tapestry5.ioc.ScopeConstants;
021import org.apache.tapestry5.ioc.annotations.Scope;
022import org.apache.tapestry5.json.JSONObject;
023import org.apache.tapestry5.runtime.RenderCommand;
024import org.apache.tapestry5.services.PartialMarkupRenderer;
025import org.apache.tapestry5.services.PartialMarkupRendererFilter;
026import org.slf4j.Logger;
027
028/**
029 * This services keeps track of the page being rendered and the root command for the partial render, it is therefore
030 * request/thread scoped. There's a filter pipeline around the rendering, and that gets to be stateless because this
031 * service, at the end of the pipeline, is stateful.
032 */
033@Scope(ScopeConstants.PERTHREAD)
034public class PageRenderQueueImpl implements PageRenderQueue
035{
036    private final LoggerSource loggerSource;
037
038    private Page page;
039
040    private boolean partialRenderInitialized;
041
042    private final Stack<PartialMarkupRendererFilter> filters = CollectionFactory.newStack();
043
044    private RenderQueueImpl queue;
045
046    private static class Bridge implements PartialMarkupRenderer
047    {
048        private final PartialMarkupRendererFilter filter;
049
050        private final PartialMarkupRenderer delegate;
051
052        private Bridge(PartialMarkupRendererFilter filter, PartialMarkupRenderer delegate)
053        {
054            this.filter = filter;
055            this.delegate = delegate;
056        }
057
058        public void renderMarkup(MarkupWriter writer, JSONObject reply)
059        {
060            filter.renderMarkup(writer, reply, delegate);
061        }
062    }
063
064    public PageRenderQueueImpl(LoggerSource loggerSource)
065    {
066        this.loggerSource = loggerSource;
067    }
068
069    public void initializeForCompletePage(Page page)
070    {
071        setRenderingPage(page);
072
073        queue.push(page.getRootElement());
074    }
075
076    public void setRenderingPage(Page page)
077    {
078        assert page != null;
079
080        this.page = page;
081
082        String name = "tapestry.render." + page.getLogger().getName();
083
084        Logger logger = loggerSource.getLogger(name);
085
086        queue = new RenderQueueImpl(logger);
087    }
088
089    public boolean isPartialRenderInitialized()
090    {
091        return partialRenderInitialized;
092    }
093
094    public void addPartialRenderer(RenderCommand renderer)
095    {
096        assert renderer != null;
097
098        checkQueue();
099
100        partialRenderInitialized = true;
101
102        queue.push(renderer);
103    }
104
105    private void checkQueue()
106    {
107        if (queue == null) {
108            throw new IllegalStateException("The page used as the basis for partial rendering has not been set.");
109        }
110    }
111
112    public Page getRenderingPage()
113    {
114        return page;
115    }
116
117    public void render(MarkupWriter writer)
118    {
119        // Run the queue until empty.
120
121        queue.run(writer);
122    }
123
124    public void addPartialMarkupRendererFilter(PartialMarkupRendererFilter filter)
125    {
126        assert filter != null;
127
128        partialRenderInitialized = true;
129
130        filters.push(filter);
131    }
132
133    public void renderPartial(MarkupWriter writer, JSONObject reply)
134    {
135        checkQueue();
136
137        PartialMarkupRenderer terminator = new PartialMarkupRenderer()
138        {
139            public void renderMarkup(MarkupWriter writer, JSONObject reply)
140            {
141                render(writer);
142            }
143        };
144
145        PartialMarkupRenderer delegate = terminator;
146
147        while (!filters.isEmpty())
148        {
149            PartialMarkupRendererFilter filter = filters.pop();
150
151            PartialMarkupRenderer bridge = new Bridge(filter, delegate);
152
153            delegate = bridge;
154        }
155
156        // The initialize methods will already have been invoked.
157
158        delegate.renderMarkup(writer, reply);
159    }
160}