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1   /*
2    * Copyright 2004 Charles Blaxland
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  package mnemosyne.core;
17  
18  
19  /***
20   * An implmentation of the Version interface based on a Java long.
21   * Provides enough capacity for most systems, especially if seeded at
22   * Long.MIN_VALUE.
23   *
24   * This object is immutable.
25   *
26   * @version $Id: LongVersion.java,v 1.1.1.1 2004/08/07 06:41:02 charlesblaxland Exp $
27   */
28  public class LongVersion implements Version
29  {
30      private long value;
31  
32      public LongVersion(long value)
33      {
34          this.value = value;
35      }
36  
37      public final Version getNext()
38      {
39          return new LongVersion(value + 1);
40      }
41  
42      public final int compareTo(Object o)
43      {
44          LongVersion other = (LongVersion) o;
45          if (this.value > other.value)
46              return 1;
47          else if (this.value < other.value)
48              return -1;
49  
50          return 0;
51      }
52  
53      public final int hashCode()
54      {
55          return (int) value;
56      }
57  
58      public final boolean equals(Object obj)
59      {
60          return obj instanceof LongVersion && this.value == ((LongVersion) obj).value;
61      }
62  
63      public final String toString()
64      {
65          return Long.toString(value);
66      }
67  }