001package org.apache.turbine.modules.layouts;
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
024import java.io.StringReader;
025
026import org.apache.commons.lang.StringUtils;
027import org.apache.commons.logging.Log;
028import org.apache.commons.logging.LogFactory;
029import org.apache.fulcrum.xslt.XSLTService;
030import org.apache.turbine.TurbineConstants;
031import org.apache.turbine.annotation.TurbineLoader;
032import org.apache.turbine.annotation.TurbineService;
033import org.apache.turbine.modules.Layout;
034import org.apache.turbine.modules.Screen;
035import org.apache.turbine.modules.ScreenLoader;
036import org.apache.turbine.pipeline.PipelineData;
037import org.apache.turbine.services.velocity.VelocityService;
038import org.apache.turbine.util.RunData;
039import org.apache.turbine.util.template.TemplateNavigation;
040import org.apache.velocity.context.Context;
041
042/**
043 * This Layout module allows Velocity XML templates to be used as layouts.
044 * <br><br>
045 * Once the (XML) screen and navigation templates have been inserted into
046 * the layout template the result is transformed with a XSL stylesheet.
047 * The stylesheet (with the same name than the screen template) is loaded
048 * and executed by the XSLT service, so it is important that you correctly
049 * set up your XSLT service.  If the named stylsheet does not exist the
050 * default.xsl stylesheet is executed.  If default.xsl does not exist
051 * the XML is merely echoed.
052 * <br><br>
053 * Since dynamic content is supposed to be primarily located in
054 * screens and navigations there should be relatively few reasons to
055 * subclass this Layout.
056 *
057 * @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>
058 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
059 * @version $Id: VelocityXslLayout.java 1773378 2016-12-09 13:19:59Z tv $
060 */
061public class VelocityXslLayout extends Layout
062{
063    /** Logging */
064    private static Log log = LogFactory.getLog(VelocityXslLayout.class);
065
066    /** The prefix for lookup up layout pages */
067    private final String prefix = Layout.PREFIX + "/";
068
069    /** Injected service instance */
070    @TurbineService
071    private VelocityService velocityService;
072
073    /** Injected service instance */
074    @TurbineService
075    private XSLTService xsltService;
076
077    /** Injected loader instance */
078    @TurbineLoader( Screen.class )
079    private ScreenLoader screenLoader;
080
081    /**
082     * Build the layout.  Also sets the ContentType and Locale headers
083     * of the HttpServletResponse object.
084     *
085     * @param pipelineData Turbine information.
086     * @throws Exception a generic exception.
087     */
088    @Override
089    public void doBuild(PipelineData pipelineData)
090        throws Exception
091    {
092        RunData data = getRunData(pipelineData);
093        // Get the context needed by Velocity.
094        Context context = velocityService.getContext(pipelineData);
095
096        data.getResponse().setContentType("text/html");
097
098        String screenName = data.getScreen();
099
100        log.debug("Loading Screen " + screenName);
101
102        // First, generate the screen and put it in the context so
103        // we can grab it the layout template.
104        String results = screenLoader.eval(pipelineData, screenName);
105        String returnValue = StringUtils.defaultIfEmpty(results, StringUtils.EMPTY);
106
107        // variable for the screen in the layout template
108        context.put(TurbineConstants.SCREEN_PLACEHOLDER, returnValue);
109
110        // variable to reference the navigation screen in the layout template
111        context.put(TurbineConstants.NAVIGATION_PLACEHOLDER,
112                    new TemplateNavigation(data));
113
114        // Grab the layout template set in the VelocityPage.
115        // If null, then use the default layout template
116        // (done by the TemplateInfo object)
117        String templateName = data.getTemplateInfo().getLayoutTemplate();
118
119        log.debug("Now trying to render layout " + templateName);
120
121        // Now, generate the layout template.
122        String temp = velocityService.handleRequest(context,
123                prefix + templateName);
124
125        // Finally we do a transformation and send the result
126        // back to the browser
127        xsltService.transform(
128            data.getTemplateInfo().getScreenTemplate(),
129                new StringReader(temp), data.getResponse().getWriter());
130    }
131}