001    // Copyright 2004, 2005 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    package org.apache.tapestry.services.impl;
015    
016    import org.apache.tapestry.IRequestCycle;
017    import org.apache.tapestry.asset.AssetFactory;
018    import org.apache.tapestry.markup.MarkupWriterSource;
019    import org.apache.tapestry.services.RequestLocaleManager;
020    import org.apache.tapestry.services.ResponseBuilder;
021    import org.apache.tapestry.services.ResponseContributor;
022    import org.apache.tapestry.web.WebRequest;
023    import org.apache.tapestry.web.WebResponse;
024    
025    import java.io.IOException;
026    
027    /**
028     * Determines if incoming request is a valid json request via the "json" http header
029     * or the "json" = "true" request parameter.
030     * 
031     * @author jkuhnert
032     */
033    public class JSONResponseContributorImpl implements ResponseContributor
034    {
035        
036        public static final String JSON_HEADER = "json";
037        
038        private RequestLocaleManager _localeManager;
039        
040        private MarkupWriterSource _markupWriterSource;
041        
042        private WebResponse _webResponse;
043        
044        private WebRequest _webRequest;
045        
046        private AssetFactory _assetFactory;
047        
048        /**
049         * {@inheritDoc}
050         */
051        public ResponseBuilder createBuilder(IRequestCycle cycle)
052        throws IOException
053        {
054            return new JSONResponseBuilder(cycle, _localeManager, _markupWriterSource,
055                    _webResponse, _webRequest, _assetFactory, _webResponse.getNamespace());
056        }
057        
058        /**
059         * {@inheritDoc}
060         */
061        public boolean handlesResponse(IRequestCycle cycle)
062        {
063            String parm = cycle.getParameter(JSON_HEADER);
064            
065            if (parm != null && Boolean.valueOf(parm).booleanValue())
066                return true;
067            if (_webRequest.getHeader(JSON_HEADER) != null)
068                return true;
069            
070            return false;
071        }
072        
073        public void setLocaleManager(RequestLocaleManager localeManager)
074        {
075            _localeManager = localeManager;
076        }
077        
078        public void setMarkupWriterSource(MarkupWriterSource markupWriterSource)
079        {
080            _markupWriterSource = markupWriterSource;
081        }
082        
083        public void setWebResponse(WebResponse webResponse)
084        {
085            _webResponse = webResponse;
086        }
087        
088        public void setWebRequest(WebRequest webRequest)
089        {
090            _webRequest  = webRequest;
091        }
092        
093        public void setAssetFactory(AssetFactory factory)
094        {
095            _assetFactory = factory;
096        }
097    }