    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 1709648 2015-10-20 17:08:10Z 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     * @exception 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}