package org.apache.turbine.modules.layouts;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied.  See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 import java.io.StringReader;

 import org.apache.commons.lang.StringUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.fulcrum.xslt.XSLTService;

 import org.apache.turbine.TurbineConstants;

 import org.apache.turbine.annotation.TurbineLoader;

 import org.apache.turbine.annotation.TurbineService;

 import org.apache.turbine.modules.Layout;

 import org.apache.turbine.modules.Screen;

 import org.apache.turbine.modules.ScreenLoader;

 import org.apache.turbine.pipeline.PipelineData;

 import org.apache.turbine.services.velocity.VelocityService;

 import org.apache.turbine.util.RunData;

 import org.apache.turbine.util.template.TemplateNavigation;

 import org.apache.velocity.context.Context;

 /**

  * This Layout module allows Velocity XML templates to be used as layouts.

  * <br><br>

  * Once the (XML) screen and navigation templates have been inserted into

  * the layout template the result is transformed with a XSL stylesheet.

  * The stylesheet (with the same name than the screen template) is loaded

  * and executed by the XSLT service, so it is important that you correctly

  * set up your XSLT service.  If the named stylsheet does not exist the

  * default.xsl stylesheet is executed.  If default.xsl does not exist

  * the XML is merely echoed.

  * <br><br>

  * Since dynamic content is supposed to be primarily located in

  * screens and navigations there should be relatively few reasons to

  * subclass this Layout.

  *

  * @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>

  * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>

  * @version $Id: VelocityXslLayout.java 1773378 2016-12-09 13:19:59Z tv $

  */

 public class VelocityXslLayout extends Layout

 {

     /** Logging */

     private static Log log = LogFactory.getLog(VelocityXslLayout.class);

     /** The prefix for lookup up layout pages */

     private final String prefix = Layout.PREFIX + "/";

     /** Injected service instance */

     @TurbineService

     private VelocityService velocityService;

     /** Injected service instance */

     @TurbineService

     private XSLTService xsltService;

     /** Injected loader instance */

     @TurbineLoader( Screen.class )

     private ScreenLoader screenLoader;

     /**

      * Build the layout.  Also sets the ContentType and Locale headers

      * of the HttpServletResponse object.

      *

      * @param pipelineData Turbine information.

      * @throws Exception a generic exception.

      */

     @Override

     public void doBuild(PipelineData pipelineData)

         throws Exception

     {

         RunData data = getRunData(pipelineData);

         // Get the context needed by Velocity.

         Context context = velocityService.getContext(pipelineData);

         data.getResponse().setContentType("text/html");

         String screenName = data.getScreen();

         log.debug("Loading Screen " + screenName);

         // First, generate the screen and put it in the context so

         // we can grab it the layout template.

         String results = screenLoader.eval(pipelineData, screenName);

         String returnValue = StringUtils.defaultIfEmpty(results, StringUtils.EMPTY);

         // variable for the screen in the layout template

         context.put(TurbineConstants.SCREEN_PLACEHOLDER, returnValue);

         // variable to reference the navigation screen in the layout template

         context.put(TurbineConstants.NAVIGATION_PLACEHOLDER,

                     new TemplateNavigation(data));

         // Grab the layout template set in the VelocityPage.

         // If null, then use the default layout template

         // (done by the TemplateInfo object)

         String templateName = data.getTemplateInfo().getLayoutTemplate();

         log.debug("Now trying to render layout " + templateName);

         // Now, generate the layout template.

         String temp = velocityService.handleRequest(context,

                 prefix + templateName);

         // Finally we do a transformation and send the result

         // back to the browser

         xsltService.transform(

             data.getTemplateInfo().getScreenTemplate(),

                 new StringReader(temp), data.getResponse().getWriter());

     }

 }