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.turbine.Turbine;
027    import org.apache.turbine.TurbineConstants;
028    import org.apache.turbine.modules.Page;
029    import org.apache.turbine.modules.PageLoader;
030    import org.apache.turbine.services.assemblerbroker.TurbineAssemblerBroker;
031    import org.apache.turbine.services.template.TemplateService;
032    import org.apache.turbine.services.template.TurbineTemplate;
033    import org.apache.turbine.util.RunData;
034    import org.apache.turbine.util.TurbineException;
035    
036    /**
037     * Implements the Page Generation portion of the "Turbine classic"
038     * processing pipeline (from the Turbine 2.x series).
039     *
040     * @author <a href="mailto:epugh@opensourceConnections.com">Eric Pugh</a>
041     * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
042     * @version $Id: ExecutePageValve.java 757213 2009-03-22 16:43:31Z tv $
043     */
044    public class ExecutePageValve
045        extends AbstractValve
046    {
047        private TemplateService templateService;
048        private PageLoader pageLoader;
049        
050        /**
051         * Creates a new instance.
052         */
053        public ExecutePageValve()
054        {
055            // empty constructor
056        }
057        
058        /**
059         * Initialize this valve for use in a pipeline.
060         * 
061         * @see org.apache.turbine.pipeline.AbstractValve#initialize()
062         */
063        public void initialize() throws Exception
064        {
065            super.initialize();
066            
067            this.templateService = TurbineTemplate.getService();
068            this.pageLoader = (PageLoader)TurbineAssemblerBroker.getLoader(Page.NAME);
069        }
070    
071        /**
072         * @see org.apache.turbine.Valve#invoke(RunData, ValveContext)
073         */
074        public void invoke(PipelineData pipelineData, ValveContext context)
075            throws IOException, TurbineException
076        {
077            try
078            {
079                executePage(pipelineData);
080            }
081            catch (Exception e)
082            {
083                throw new TurbineException(e);
084            }
085    
086            // Pass control to the next Valve in the Pipeline
087            context.invokeNext(pipelineData);
088        }
089    
090        /**
091         * execute the page generation.
092         *
093         * @param data The run-time data.
094         */
095        protected void executePage(PipelineData pipelineData)
096            throws Exception
097        {
098            RunData data = getRunData(pipelineData);
099    
100            // Start the execution phase. DefaultPage will execute the
101            // appropriate action as well as get the Layout from the
102            // Screen and then execute that. The Layout is then
103            // responsible for executing the Navigation and Screen
104            // modules.
105            //
106            // Note that by default, this cannot be overridden from
107            // parameters passed in via post/query data. This is for
108            // security purposes.  You should really never need more
109            // than just the default page.  If you do, add logic to
110            // DefaultPage to do what you want.
111    
112            String defaultPage = (templateService == null)
113            ? null :templateService.getDefaultPageName(data);
114    
115            if (defaultPage == null)
116            {
117                /*
118                 * In this case none of the template services are running.
119                 * The application may be using ECS for views, or a
120                 * decendent of RawScreen is trying to produce output.
121                 * If there is a 'page.default' property in the TR.props
122                 * then use that, otherwise return DefaultPage which will
123                 * handle ECS view scenerios and RawScreen scenerios. The
124                 * app developer can still specify the 'page.default'
125                 * if they wish but the DefaultPage should work in
126                 * most cases.
127                 */
128                defaultPage = Turbine.getConfiguration().getString(TurbineConstants.PAGE_DEFAULT_KEY,
129                        TurbineConstants.PAGE_DEFAULT_DEFAULT);
130            }
131    
132            pageLoader.exec(pipelineData, defaultPage);
133        }
134    }