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1   package org.apache.turbine.util.template;
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.commons.logging.Log;
25  import org.apache.commons.logging.LogFactory;
26  import org.apache.turbine.modules.Screen;
27  import org.apache.turbine.modules.ScreenLoader;
28  import org.apache.turbine.services.assemblerbroker.TurbineAssemblerBroker;
29  import org.apache.turbine.util.RunData;
30  
31  /**
32   * Returns output of a Screen module.  An instance of this is
33   * placed in the Velocity context by the VelocityDirectLayout.  This
34   * allows the screen to be executed only at rendering.
35   * Here's how it's used in a template:
36   *
37   * <p>
38   * <code>
39   * $screen_placeholder
40   * </code>
41   * <p>
42   * <code>
43   * $screen_placeholder.setScreen("Test")
44   * </code>
45   * </p>
46   *
47   * @author <a href="raphael@apache.org">Raphaƫl Luta</a>
48   * @version $Id: TemplateScreen.java 1709648 2015-10-20 17:08:10Z tv $
49   */
50  public class TemplateScreen
51  {
52      /** Logging */
53      private static Log log = LogFactory.getLog(TemplateScreen.class);
54  
55      /* The RunData object. */
56      private final RunData data;
57  
58      /* The name of the screen template. */
59      private String screen;
60  
61      private final ScreenLoader screenLoader;
62  
63      /**
64       * Constructor
65       *
66       * @param data A Turbine RunData object.
67       */
68      public TemplateScreen(RunData data)
69      {
70          this.data = data;
71          this.screen = data.getScreen();
72          this.screenLoader = (ScreenLoader)TurbineAssemblerBroker.getLoader(Screen.class);
73      }
74  
75      /**
76       * Set the screen.
77       *
78       * @param screen A String with the name of the screen module
79       * @return A TemplateScreen (self).
80       */
81      public TemplateScreen setScreen(String screen)
82      {
83          this.screen = screen;
84          return this;
85      }
86  
87      /**
88       * Builds the output of the navigation template.
89       *
90       * @return A String.
91       */
92      @Override
93      public String toString()
94      {
95          String returnValue = "";
96  
97          try
98          {
99              String results = screenLoader.eval(data, this.screen);
100 
101             if (results != null)
102             {
103                 returnValue = results;
104             }
105         }
106         catch (Exception e)
107         {
108             log.error(e);
109         }
110 
111         return returnValue;
112     }
113 }