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1   /*
2   * The contents of this file are subject to the BT "ZEUS" Open Source 
3   * Licence (L77741), Version 1.0 (the "Licence"); you may not use this file 
4   * except in compliance with the Licence. You may obtain a copy of the Licence
5   * from $ZEUS_INSTALL/licence.html or alternatively from
6   * http://www.labs.bt.com/projects/agents/zeus/licence.htm
7   * 
8   * Except as stated in Clause 7 of the Licence, software distributed under the
9   * Licence is distributed WITHOUT WARRANTY OF ANY KIND, either express or 
10  * implied. See the Licence for the specific language governing rights and 
11  * limitations under the Licence.
12  * 
13  * The Original Code is within the package zeus.*.
14  * The Initial Developer of the Original Code is British Telecommunications
15  * public limited company, whose registered office is at 81 Newgate Street, 
16  * London, EC1A 7AJ, England. Portions created by British Telecommunications 
17  * public limited company are Copyright 1996-9. All Rights Reserved.
18  * 
19  * THIS NOTICE MUST BE INCLUDED ON ANY COPY OF THIS FILE
20  */
21  
22  
23  
24  package zeus.util;
25  
26  import java.util.*;
27  
28  public class HSet {
29     private static final String NONE = "NONE";
30     protected Hashtable table;
31  
32     public HSet() {
33        table = new Hashtable();
34     }
35     public HSet(int capacity) {
36        table = new Hashtable(capacity);
37     }
38     public HSet(int capacity, float loadFactor) {
39        table = new Hashtable(capacity, loadFactor);
40     }
41  
42     public synchronized Enumeration elements() {
43        return table.keys();
44     }
45     public synchronized void add(HSet input) {
46        Enumeration enum = input.elements();
47        while( enum.hasMoreElements() )
48           table.put(enum.nextElement(),NONE);
49     }
50     public synchronized void add(Object data) {
51        table.put(data,NONE);
52     }
53  
54     public synchronized void remove(Object data) {
55        table.remove(data);
56     }
57  
58     public synchronized void clear() {
59        table.clear();
60     }
61     public synchronized Object clone() {
62        return null;
63     }
64     public synchronized int size() {
65        return table.size();
66     }
67     public synchronized boolean isEmpty() {
68        return table.isEmpty();
69     }
70     public synchronized boolean contains(Object data) {
71        return table.containsKey(data);
72     }
73     public synchronized Vector toVector() {
74        Vector output = new Vector();
75        Enumeration enum = table.keys();
76        while( enum.hasMoreElements() )
77           output.addElement(enum.nextElement());
78        return output;
79     }
80  }