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1   package org.apache.turbine.modules.layouts;
2   
3   
4   /*
5    * Licensed to the Apache Software Foundation (ASF) under one
6    * or more contributor license agreements.  See the NOTICE file
7    * distributed with this work for additional information
8    * regarding copyright ownership.  The ASF licenses this file
9    * to you under the Apache License, Version 2.0 (the
10   * "License"); you may not use this file except in compliance
11   * with the License.  You may obtain a copy of the License at
12   *
13   *   http://www.apache.org/licenses/LICENSE-2.0
14   *
15   * Unless required by applicable law or agreed to in writing,
16   * software distributed under the License is distributed on an
17   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
18   * KIND, either express or implied.  See the License for the
19   * specific language governing permissions and limitations
20   * under the License.
21   */
22  
23  
24  import java.io.StringReader;
25  
26  import org.apache.commons.lang.StringUtils;
27  import org.apache.commons.logging.Log;
28  import org.apache.commons.logging.LogFactory;
29  import org.apache.fulcrum.xslt.XSLTService;
30  import org.apache.turbine.TurbineConstants;
31  import org.apache.turbine.annotation.TurbineLoader;
32  import org.apache.turbine.annotation.TurbineService;
33  import org.apache.turbine.modules.Layout;
34  import org.apache.turbine.modules.Screen;
35  import org.apache.turbine.modules.ScreenLoader;
36  import org.apache.turbine.pipeline.PipelineData;
37  import org.apache.turbine.services.velocity.VelocityService;
38  import org.apache.turbine.util.RunData;
39  import org.apache.turbine.util.template.TemplateNavigation;
40  import org.apache.velocity.context.Context;
41  
42  /**
43   * This Layout module allows Velocity XML templates to be used as layouts.
44   * <br><br>
45   * Once the (XML) screen and navigation templates have been inserted into
46   * the layout template the result is transformed with a XSL stylesheet.
47   * The stylesheet (with the same name than the screen template) is loaded
48   * and executed by the XSLT service, so it is important that you correctly
49   * set up your XSLT service.  If the named stylsheet does not exist the
50   * default.xsl stylesheet is executed.  If default.xsl does not exist
51   * the XML is merely echoed.
52   * <br><br>
53   * Since dynamic content is supposed to be primarily located in
54   * screens and navigations there should be relatively few reasons to
55   * subclass this Layout.
56   *
57   * @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>
58   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
59   * @version $Id: VelocityXslLayout.java 1709648 2015-10-20 17:08:10Z tv $
60   */
61  public class VelocityXslLayout extends Layout
62  {
63      /** Logging */
64      private static Log log = LogFactory.getLog(VelocityXslLayout.class);
65  
66      /** The prefix for lookup up layout pages */
67      private final String prefix = Layout.PREFIX + "/";
68  
69      /** Injected service instance */
70      @TurbineService
71      private VelocityService velocityService;
72  
73      /** Injected service instance */
74      @TurbineService
75      private XSLTService xsltService;
76  
77      /** Injected loader instance */
78      @TurbineLoader( Screen.class )
79      private ScreenLoader screenLoader;
80  
81      /**
82       * Build the layout.  Also sets the ContentType and Locale headers
83       * of the HttpServletResponse object.
84       *
85       * @param pipelineData Turbine information.
86       * @exception Exception a generic exception.
87       */
88      @Override
89      public void doBuild(PipelineData pipelineData)
90          throws Exception
91      {
92          RunData data = getRunData(pipelineData);
93          // Get the context needed by Velocity.
94          Context context = velocityService.getContext(pipelineData);
95  
96          data.getResponse().setContentType("text/html");
97  
98          String screenName = data.getScreen();
99  
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 }