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1   /*
2    * Copyright (c) 1998-2002 The Jgroup Team.
3    *
4    * This program is free software; you can redistribute it and/or modify
5    * it under the terms of the GNU Lesser General Public License version 2 as
6    * published by the Free Software Foundation.
7    *
8    * This program is distributed in the hope that it will be useful,
9    * but WITHOUT ANY WARRANTY; without even the implied warranty of
10   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11   * GNU Lesser General Public License for more details.
12   *
13   * You should have received a copy of the GNU Lesser General Public License
14   * along with this program; if not, write to the Free Software
15   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
16   *
17   */
18  
19  package jgroup.relacs.types;
20  
21  import java.io.IOException;
22  import java.io.ObjectInput;
23  import java.io.ObjectOutput;
24  
25  /**
26   *  The <code>GroupIndex</code> class wraps a value of the relacs daemon
27   *  type "group index" in an object.  A group index is used to uniquely
28   *  identify members of a group through their index in the current view.
29   *
30   *  @author Alberto Montresor
31   *  @since Jgroup 1.2
32   */
33  public final class GroupIndex
34  {
35    
36    ////////////////////////////////////////////////////////////////////////////////////////////
37    // Constants
38    ////////////////////////////////////////////////////////////////////////////////////////////
39  
40    /** Size of this object in bytes */
41    public static final int SIZE = 2;
42  
43  
44    ////////////////////////////////////////////////////////////////////////////////////////////
45    // Fields
46    ////////////////////////////////////////////////////////////////////////////////////////////
47    
48    /** Wrapped value */
49    private int value;
50  
51  
52    ////////////////////////////////////////////////////////////////////////////////////////////
53    // Constructor
54    ////////////////////////////////////////////////////////////////////////////////////////////
55    
56    /**
57     *  Creates a <CODE>GroupIndex</CODE> object containing the specified
58     *  value.
59     */
60    public GroupIndex(int value)
61    {
62      this.value = value;
63    }
64    
65    
66    ////////////////////////////////////////////////////////////////////////////////////////////
67    // Accessor method
68    ////////////////////////////////////////////////////////////////////////////////////////////
69    
70    /**
71     *  Returned the wrapped value.
72     */
73    public int getValue()
74    {
75      return value;
76    }
77    
78    ////////////////////////////////////////////////////////////////////////////////////////////
79    // Marshaling / unmarshaling methods
80    ////////////////////////////////////////////////////////////////////////////////////////////
81    
82    /**
83     *  Marshals the specified group index to an outgoing message.
84     */
85    public static void marshal(ObjectOutput msg, int value)
86      throws IOException
87    {
88      msg.writeShort(value);
89    }
90    
91    /**
92     *  Unmarshals a group index from an incoming message.
93     */
94    public static int unmarshal(ObjectInput msg)
95      throws IOException
96    {
97      return msg.readShort();
98    }
99  
100 } // END GroupIndex