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1   package org.apache.turbine.modules.pages;
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 org.apache.turbine.pipeline.PipelineData;
25  import org.apache.turbine.services.template.TurbineTemplate;
26  import org.apache.turbine.util.RunData;
27  import org.apache.turbine.util.TurbineException;
28  
29  /**
30   * When building sites using templates, Screens need only be defined
31   * for templates which require dynamic (database or object) data.
32   *
33   * <p>
34   *
35   * This page can be used on sites where the number of Screens can be
36   * much less than the number of templates.  The templates can be
37   * grouped in directories with common layouts.  Screen modules are
38   * then expected to be placed in packages corresponding with the
39   * templates' directories and follow a specific naming scheme.
40   *
41   * <p>
42   *
43   * The template parameter is parsed and and a Screen whose package
44   * matches the templates path and shares the same name minus any
45   * extension and beginning with a capital letter is searched for.  If
46   * not found, a Screen in a package matching the template's path with
47   * name Default is searched for.  If still not found, a Screen with
48   * name Default is looked for in packages corresponding to parent
49   * directories in the template's path until a match is found.
50   *
51   * <p>
52   *
53   * For example if data.getParameters().getString("template") returns
54   * /about_us/directions/driving.wm, the search follows
55   * about_us.directions.Driving, about_us.directions.Default,
56   * about_us.Default, Default, WebMacroSiteScreen (i.e. the default
57   * screen set in TurbineResources).
58   *
59   * <p>
60   *
61   * Only one Layout module is used, since it is expected that any
62   * dynamic content will be placed in navigations and screens.  The
63   * layout template to be used is found in a similar way to the Screen.
64   * For example the following paths will be searched in the layouts
65   * subdirectory: /about_us/directions/driving.wm,
66   * /about_us/directions/default.wm, /about_us/default.wm, /default.wm,
67   * where wm is the value of the template.default.extension property.
68   *
69   * <p>
70   *
71   * This approach allows a site with largely static content to be
72   * updated and added to regularly by those with little Java
73   * experience.
74   *
75   * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
76   * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
77   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
78   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
79   * @version $Id: TemplatePage.java 1078552 2011-03-06 19:58:46Z tv $
80   */
81  public class TemplatePage
82      extends DefaultPage
83  {
84      /**
85       * Works with TemplateService to set up default templates and
86       * corresponding class modules.
87       *
88       * @param data Turbine information.
89       * @exception Exception, a generic exception.
90       */
91      @Override
92      protected void doBuildAfterAction(RunData data)
93          throws Exception
94      {
95          // The Template Service at this point must fetch the Screen class
96          // to match a given template. If the Screen class has already been
97          // set by an action, skip this, because the user has the already
98          // specified the Screen class he wants to use.
99          if (!data.hasScreen())
100         {
101             // This is effectively getting the "template" parameter
102             // from the parameter parser in rundata. This is coming
103             // from the request for a template.
104             String template = data.getTemplateInfo().getScreenTemplate();
105 
106             // Get the layout template and the correct Screen.
107             String layoutTemplate =
108                     TurbineTemplate.getLayoutTemplateName(template);
109             data.getTemplateInfo().setLayoutTemplate(layoutTemplate);
110 
111             String screen = TurbineTemplate.getScreenName(template);
112 
113             if (screen == null)
114             {
115                 String errMsg = "Couldn't map Template "
116                     + template + " to any Screen class!";
117                 log.error(errMsg);
118                 throw new TurbineException(errMsg);
119             }
120             data.setScreen(screen);
121         }
122     }
123 
124     /**
125      * Works with TemplateService to set up default templates and
126      * corresponding class modules.
127      *
128      * @param pipelineData Turbine information.
129      * @exception Exception, a generic exception.
130      */
131     @Override
132     protected void doBuildAfterAction(PipelineData pipelineData)
133         throws Exception
134     {
135         RunData data = getRunData(pipelineData);
136         doBuildAfterAction(data);
137     }
138 
139 
140 
141 }