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    
015    package org.apache.tapestry.contrib.ajax;
016    
017    import java.io.IOException;
018    import java.io.OutputStream;
019    import java.io.StringWriter;
020    import java.util.HashMap;
021    import java.util.Map;
022    
023    import javax.xml.parsers.DocumentBuilder;
024    import javax.xml.parsers.DocumentBuilderFactory;
025    import javax.xml.transform.OutputKeys;
026    import javax.xml.transform.Transformer;
027    import javax.xml.transform.TransformerFactory;
028    import javax.xml.transform.dom.DOMSource;
029    import javax.xml.transform.stream.StreamResult;
030    
031    import org.apache.hivemind.ApplicationRuntimeException;
032    import org.apache.hivemind.util.Defense;
033    import org.apache.tapestry.IComponent;
034    import org.apache.tapestry.IPage;
035    import org.apache.tapestry.IRequestCycle;
036    import org.apache.tapestry.engine.IEngineService;
037    import org.apache.tapestry.engine.ILink;
038    import org.apache.tapestry.error.RequestExceptionReporter;
039    import org.apache.tapestry.request.RequestContext;
040    import org.apache.tapestry.services.LinkFactory;
041    import org.apache.tapestry.services.ServiceConstants;
042    import org.apache.tapestry.util.ContentType;
043    import org.apache.tapestry.web.WebResponse;
044    import org.w3c.dom.Document;
045    import org.w3c.dom.Node;
046    
047    /**
048     * @author mindbridge
049     * @author Paul Green
050     * @since 4.0
051     */
052    public class XTileService implements IEngineService
053    {
054        public static final String SERVICE_NAME = "xtile";
055    
056        private RequestExceptionReporter _exceptionReporter;
057    
058        private WebResponse _response;
059        
060        private LinkFactory _linkFactory;
061    
062        public String getName()
063        {
064            return SERVICE_NAME;
065        }
066    
067        public ILink getLink(boolean post, Object parameter)
068        {
069            Defense.isAssignable(parameter, IComponent.class, "parameter");
070    
071            IComponent component = (IComponent) parameter;
072    
073            Map parameters = new HashMap();
074            parameters.put(ServiceConstants.PAGE, component.getPage().getPageName());
075            parameters.put(ServiceConstants.COMPONENT, component.getIdPath());
076    
077            return _linkFactory.constructLink(this, false, parameters, false);
078        }
079    
080        public void service(IRequestCycle cycle) throws IOException
081        {
082            String pageName = cycle.getParameter(ServiceConstants.PAGE);
083            String componentId = cycle.getParameter(ServiceConstants.COMPONENT);
084    
085            IPage componentPage = cycle.getPage(pageName);
086            IComponent component = componentPage.getNestedComponent(componentId);
087    
088            if (!(component instanceof IXTile))
089                throw new ApplicationRuntimeException("Incorrect component type: was "
090                        + component.getClass() + " but must be " + IXTile.class, component, null, null);
091    
092            IXTile xtile = (IXTile) component;
093    
094            // do not squeeze on input
095            RequestContext context = cycle.getRequestContext();
096            String[] params = context.getParameters(ServiceConstants.PARAMETER);
097            cycle.setServiceParameters(params);
098            xtile.trigger(cycle);
099    
100            // do not squeeze on output either
101            Object[] args = cycle.getServiceParameters();
102            String strArgs = generateOutputString(args);
103            if (strArgs != null)
104            {
105                OutputStream output = _response.getOutputStream(new ContentType("text/xml"));
106                output.write(strArgs.getBytes("utf-8"));
107            }
108        }
109    
110        protected String generateOutputString(Object[] args)
111        {
112            try
113            {
114                DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
115                dbf.setValidating(false);
116                DocumentBuilder db = dbf.newDocumentBuilder();
117                Document doc = db.newDocument();
118    
119                Node rootNode = doc.createElement("data");
120                doc.appendChild(rootNode);
121    
122                if (args != null)
123                {
124                    for (int i = 0; i < args.length; i++)
125                    {
126                        Object value = args[i];
127    
128                        Node spNode = doc.createElement("sp");
129                        rootNode.appendChild(spNode);
130    
131                        Node valueNode = doc.createTextNode(value.toString());
132                        spNode.appendChild(valueNode);
133                    }
134                }
135    
136                TransformerFactory trf = TransformerFactory.newInstance();
137                Transformer tr = trf.newTransformer();
138                tr.setOutputProperty(OutputKeys.INDENT, "yes");
139    
140                DOMSource domSrc = new DOMSource(doc);
141                StringWriter writer = new StringWriter();
142                StreamResult res = new StreamResult(writer);
143                tr.transform(domSrc, res);
144                writer.close();
145    
146                return writer.toString();
147            }
148            catch (Exception e)
149            {
150                _exceptionReporter.reportRequestException("Cannot generate XML", e);
151                return null;
152            }
153        }
154    
155        public void setExceptionReporter(RequestExceptionReporter exceptionReporter)
156        {
157            _exceptionReporter = exceptionReporter;
158        }
159    
160        public void setResponse(WebResponse response)
161        {
162            _response = response;
163        }
164    
165        public static void main(String[] args)
166        {
167            XTileService objService = new XTileService();
168            System.out.println(objService.generateOutputString(new Object[]
169            { "test > work", new Integer(20) }));
170        }
171    
172        public void setLinkFactory(LinkFactory linkFactory)
173        {
174            _linkFactory = linkFactory;
175        }
176    
177    }