001    // Copyright 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.Tapestry;
019    import org.apache.tapestry.engine.ServiceEncoder;
020    import org.apache.tapestry.engine.ServiceEncoding;
021    import org.apache.tapestry.services.ServiceConstants;
022    
023    /**
024     * A specialized encoder for the {@link org.apache.tapestry.engine.DirectService direct service}
025     *  that encodes the page name and component id path into the servlet path, and encodes the
026     * stateful flag by choosing one of two extensions.
027     * 
028     * @author Howard M. Lewis Ship
029     * @since 4.0
030     */
031    public class DirectServiceEncoder implements ServiceEncoder
032    {
033        private String _statelessExtension;
034    
035        private String _statefulExtension;
036    
037        public void encode(ServiceEncoding encoding)
038        {
039            String service = encoding.getParameterValue(ServiceConstants.SERVICE);
040            if (!service.equals(Tapestry.DIRECT_SERVICE))
041                return;
042    
043            String pageName = encoding.getParameterValue(ServiceConstants.PAGE);
044    
045            // Only handle pages in the application namespace (not from a library).
046    
047            if (pageName.indexOf(INamespace.SEPARATOR) >= 0)
048                return;
049    
050            String stateful = encoding.getParameterValue(ServiceConstants.SESSION);
051            String componentIdPath = encoding.getParameterValue(ServiceConstants.COMPONENT);
052    
053            StringBuffer buffer = new StringBuffer("/");
054            buffer.append(pageName);
055    
056            buffer.append(",");
057            buffer.append(componentIdPath);
058    
059            buffer.append(".");
060            buffer.append(stateful != null ? _statefulExtension : _statelessExtension);
061    
062            encoding.setServletPath(buffer.toString());
063    
064            encoding.setParameterValue(ServiceConstants.SERVICE, null);
065            encoding.setParameterValue(ServiceConstants.PAGE, null);
066            encoding.setParameterValue(ServiceConstants.SESSION, null);
067            encoding.setParameterValue(ServiceConstants.COMPONENT, null);
068        }
069    
070        public void decode(ServiceEncoding encoding)
071        {
072            String servletPath = encoding.getServletPath();
073    
074            int dotx = servletPath.lastIndexOf('.');
075            if (dotx < 0)
076                return;
077    
078            String extension = servletPath.substring(dotx + 1);
079    
080            if (!(extension.equals(_statefulExtension) || extension.equals(_statelessExtension)))
081                return;
082    
083            int commax = servletPath.lastIndexOf(',');
084    
085            String pageName = servletPath.substring(1, commax);
086            String componentIdPath = servletPath.substring(commax + 1, dotx);
087    
088            encoding.setParameterValue(ServiceConstants.SERVICE, Tapestry.DIRECT_SERVICE);
089            encoding.setParameterValue(ServiceConstants.PAGE, pageName);
090            encoding.setParameterValue(
091                    ServiceConstants.SESSION,
092                    extension.equals(_statefulExtension) ? "T" : null);
093            encoding.setParameterValue(ServiceConstants.COMPONENT, componentIdPath);
094        }
095    
096        public void setStatefulExtension(String statefulExtension)
097        {
098            _statefulExtension = statefulExtension;
099        }
100    
101        public void setStatelessExtension(String statelessExtension)
102        {
103            _statelessExtension = statelessExtension;
104        }
105    }