001    package org.apache.turbine.pipeline;
002    
003    
004    /*
005     * Licensed to the Apache Software Foundation (ASF) under one
006     * or more contributor license agreements.  See the NOTICE file
007     * distributed with this work for additional information
008     * regarding copyright ownership.  The ASF licenses this file
009     * to you under the Apache License, Version 2.0 (the
010     * "License"); you may not use this file except in compliance
011     * with the License.  You may obtain a copy of the License at
012     *
013     *   http://www.apache.org/licenses/LICENSE-2.0
014     *
015     * Unless required by applicable law or agreed to in writing,
016     * software distributed under the License is distributed on an
017     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
018     * KIND, either express or implied.  See the License for the
019     * specific language governing permissions and limitations
020     * under the License.
021     */
022    
023    
024    import java.io.IOException;
025    
026    import org.apache.commons.logging.Log;
027    import org.apache.commons.logging.LogFactory;
028    import org.apache.turbine.util.RunData;
029    import org.apache.turbine.util.TurbineException;
030    import org.apache.turbine.util.uri.URIConstants;
031    
032    /**
033     * This valve is responsible for setting the 'target' property of the RunData.
034     * If it is not already set it attempts to get the target from the request
035     * parameter 'template'. If the parameter is not set, we use the homepage
036     * specified by the configuration property Turbine.TEMPLATE_HOMEPAGE.
037     *
038     * FIXME: The request parameter which determines the template should be
039     *        configurable.
040     *
041     * @author <a href="mailto:james@jamestaylor.org">James Taylor</a>
042     * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
043     */
044    public class DetermineTargetValve
045        extends AbstractValve
046    {
047        private static final Log log
048            = LogFactory.getLog(DetermineTargetValve.class);
049    
050        /**
051         * @see org.apache.turbine.Valve#invoke(RunData, ValveContext)
052         */
053        public void invoke(PipelineData pipelineData, ValveContext context)
054            throws IOException, TurbineException
055        {
056            RunData runData = getRunData(pipelineData);
057            if (! runData.hasScreen())
058            {
059                String target = runData.getParameters().getString(URIConstants.CGI_SCREEN_PARAM);
060    
061                if (target != null)
062                {
063                    runData.setScreen(target);
064    
065                    log.debug("Set screen target from request parameter");
066                }
067                else
068                {
069                /*    data.setScreen(Turbine.getConfiguration().getString(
070                        Turbine.TEMPLATE_HOMEPAGE));
071    
072                    log.debug("Set target using default value");
073                    */
074                                    log.debug("No target screen");
075                }
076    
077            }
078    
079            if (log.isDebugEnabled())
080            {
081                log.debug("Screen Target is now: " + runData.getScreen());
082            }
083    
084            // Pass control to the next Valve in the Pipeline
085            context.invokeNext(pipelineData);
086        }
087    }