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1   /*--------------------------------------------------------------------------
2    *  Copyright 2007 utgenome.org
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License");
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License.
15   *--------------------------------------------------------------------------*/
16  //--------------------------------------
17  // Aqua Project
18  //
19  // TabEntry.java
20  // Since: 2007/03/24
21  //
22  // $URL$ 
23  // $Author$
24  //--------------------------------------
25  package org.utgenome.gwt.utgb.client.ui.tab;
26  
27  import com.google.gwt.user.client.ui.Composite;
28  
29  /**
30   * A TabEntry is a single panel of the TabViewer. They are meant to be lazily
31   * instantiated so that the viewer doesn't load all of the tabbed panels.
32   * 
33   * Each TabEntry is expected to have a static <code>factory()</code> method that
34   * will be called by the TabViewer on startup.
35   * 
36   * <code>createInstance()</code> must be defined in eath TabEntryFactory.
37   * 
38   * Example: <code>
39   * clsss MyTab extends TabEntry
40   * {
41   *    pubic static TabEntryFactory factory()
42   *    {
43   *        return new TabEntryFactory("my tab", "a description of the tab") {
44   * 		 	 public TabEntry createInstance() {
45   * 			 	return new MyTab();
46   * 			 }
47   * 		  };
48   *    }
49   * }
50   * </code>
51   * 
52   * @author leo
53   * 
54   */
55  public abstract class TabEntry extends Composite implements TabEventListener
56  {
57  
58      /**
59       * Encapsulated information about a TabEntry.
60       * 
61       * @author leo
62       */
63      public abstract static class TabEntryFactory
64      {
65          private TabEntry _instance = null;
66  
67          private String _tabName, _description;
68  
69          public TabEntryFactory(String name, String description)
70          {
71              _tabName = name;
72              _description = description;
73          }
74  
75          public String getDescription()
76          {
77              return _description;
78          }
79  
80          public String getTabName()
81          {
82              return _tabName;
83          }
84  
85          public abstract TabEntry createInstance();
86  
87          public boolean isInstanciated()
88          {
89              return _instance != null;
90          }
91  
92          public final TabEntry getInstance()
93          {
94              if (_instance != null)
95                  return _instance;
96  
97              return (_instance = createInstance());
98          }
99      }
100 
101     public void onFocus()
102     {
103     // do nothing
104     }
105 
106     public void onLostFocus()
107     {
108     // do nothing
109     }
110 
111 }