001    // Copyright 2007, 2008, 2009 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.ContentType;
018    import org.apache.tapestry5.MarkupWriter;
019    import org.apache.tapestry5.SymbolConstants;
020    import org.apache.tapestry5.internal.InternalConstants;
021    import org.apache.tapestry5.ioc.annotations.Inject;
022    import org.apache.tapestry5.ioc.annotations.Symbol;
023    import org.apache.tapestry5.json.JSONObject;
024    import org.apache.tapestry5.services.MarkupWriterFactory;
025    import org.apache.tapestry5.services.PartialMarkupRenderer;
026    import org.apache.tapestry5.services.Request;
027    import org.apache.tapestry5.services.Response;
028    
029    import java.io.IOException;
030    import java.io.PrintWriter;
031    
032    public class AjaxPartialResponseRendererImpl implements AjaxPartialResponseRenderer
033    {
034        private final MarkupWriterFactory factory;
035    
036        private final Request request;
037    
038        private final Response response;
039    
040        private final PartialMarkupRenderer partialMarkupRenderer;
041    
042        private final String outputEncoding;
043    
044        public AjaxPartialResponseRendererImpl(MarkupWriterFactory factory,
045    
046                                               Request request,
047    
048                                               Response response,
049    
050                                               PartialMarkupRenderer partialMarkupRenderer,
051    
052                                               @Inject @Symbol(SymbolConstants.CHARSET)
053                                               String outputEncoding)
054        {
055            this.factory = factory;
056            this.request = request;
057            this.response = response;
058            this.partialMarkupRenderer = partialMarkupRenderer;
059            this.outputEncoding = outputEncoding;
060        }
061    
062        public void renderPartialPageMarkup() throws IOException
063        {
064            // This is a complex area as we are trying to keep public and private services properly
065            // seperated, and trying to keep stateless and stateful (i.e., perthread scope) services
066            // seperated. So we inform the stateful queue service what it needs to do here ...
067    
068            ContentType pageContentType =
069                    (ContentType) request.getAttribute(InternalConstants.CONTENT_TYPE_ATTRIBUTE_NAME);
070    
071            ContentType contentType = new ContentType(InternalConstants.JSON_MIME_TYPE, outputEncoding);
072    
073            MarkupWriter writer = factory.newPartialMarkupWriter(pageContentType);
074    
075            JSONObject reply = new JSONObject();
076    
077            // ... and here, the pipeline eventually reaches the PRQ to let it render the root render command.
078    
079            partialMarkupRenderer.renderMarkup(writer, reply);
080    
081            PrintWriter pw = response.getPrintWriter(contentType.toString());
082    
083            pw.print(reply);
084    
085            pw.close();
086        }
087    }