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.engine.encoders;
016    
017    import org.apache.tapestry.INamespace;
018    import org.apache.tapestry.engine.ServiceEncoder;
019    import org.apache.tapestry.engine.ServiceEncoding;
020    import org.apache.tapestry.services.ServiceConstants;
021    
022    /**
023     * The canonical implementation of
024     * {@link org.apache.tapestry.engine.ServiceEncoder}, it encodes page name and
025     * a service name. The page name becomes the servlet path, prefixed with "/" and
026     * suffixed with a dot and a particular extension. In this way,
027     * "/app?service=page&page=Home" becomes simply "Home.html". This is most
028     * suitable for the "page" and "external" services.
029     * 
030     * @author Howard M. Lewis Ship
031     * @since 4.0
032     */
033    public class PageServiceEncoder implements ServiceEncoder
034    {
035    
036        private String _extension;
037    
038        private String _serviceName;
039    
040        public void encode(ServiceEncoding encoding)
041        {
042            String service = encoding.getParameterValue(ServiceConstants.SERVICE);
043    
044            if (!service.equals(_serviceName)) return;
045    
046            String pageName = encoding.getParameterValue(ServiceConstants.PAGE);
047    
048            // Only handle pages in the application namespace (not from a library).
049    
050            if (pageName.indexOf(INamespace.SEPARATOR) >= 0) return;
051    
052            StringBuffer buffer = new StringBuffer("/");
053            buffer.append(pageName);
054            buffer.append('.');
055            buffer.append(_extension);
056    
057            encoding.setServletPath(buffer.toString());
058    
059            encoding.setParameterValue(ServiceConstants.SERVICE, null);
060            encoding.setParameterValue(ServiceConstants.PAGE, null);
061        }
062    
063        public void decode(ServiceEncoding encoding)
064        {
065            String servletPath = encoding.getServletPath();
066    
067            int dotx = servletPath.lastIndexOf('.');
068            if (dotx < 0) return;
069    
070            String extension = servletPath.substring(dotx + 1);
071    
072            if (!extension.equals(_extension)) return;
073    
074            // Skip the slash and the dot.
075    
076            String page = servletPath.substring(1, dotx);
077    
078            encoding.setParameterValue(ServiceConstants.SERVICE, _serviceName);
079            encoding.setParameterValue(ServiceConstants.PAGE, page);
080        }
081    
082        public void setExtension(String extension)
083        {
084            _extension = extension;
085        }
086    
087        public void setServiceName(String serviceName)
088        {
089            _serviceName = serviceName;
090        }
091    }