1   /**
2    * Copyright (c) 2000-2009 Liferay, Inc. All rights reserved.
3    *
4    * Permission is hereby granted, free of charge, to any person obtaining a copy
5    * of this software and associated documentation files (the "Software"), to deal
6    * in the Software without restriction, including without limitation the rights
7    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8    * copies of the Software, and to permit persons to whom the Software is
9    * furnished to do so, subject to the following conditions:
10   *
11   * The above copyright notice and this permission notice shall be included in
12   * all copies or substantial portions of the Software.
13   *
14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20   * SOFTWARE.
21   */
22  
23  package com.liferay.portal.kernel.util;
24  
25  import java.util.AbstractSet;
26  import java.util.Iterator;
27  import java.util.Map;
28  import java.util.Set;
29  import java.util.concurrent.ConcurrentHashMap;
30  
31  /**
32   * <a href="ConcurrentHashSet.java.html"><b><i>View Source</i></b></a>
33   *
34   * @author Brian Wing Shun Chan
35   *
36   */
37  public class ConcurrentHashSet<E> extends AbstractSet<E> {
38  
39      public ConcurrentHashSet() {
40          _map = new ConcurrentHashMap<E, String>();
41      }
42  
43      public ConcurrentHashSet(int capacity) {
44          _map = new ConcurrentHashMap<E, String>(capacity);
45      }
46  
47      public ConcurrentHashSet(Set<E> set) {
48          Iterator<E> itr = set.iterator();
49  
50          while (itr.hasNext()) {
51              E e = itr.next();
52  
53              _map.put(e, StringPool.BLANK);
54          }
55      }
56  
57      public boolean add(E e) {
58          if (_map.put(e, StringPool.BLANK) == null) {
59              return true;
60          }
61          else {
62              return false;
63          }
64      }
65  
66      public void clear() {
67          _map.clear();
68      }
69  
70      public boolean contains(Object obj) {
71          if (_map.containsKey(obj)) {
72              return true;
73          }
74          else {
75              return false;
76          }
77      }
78  
79      public Iterator<E> iterator() {
80          return _map.keySet().iterator();
81      }
82  
83      public boolean remove(Object obj) {
84          if (_map.remove(obj) == null) {
85              return false;
86          }
87          else {
88              return true;
89          }
90      }
91  
92      public int size() {
93          return _map.size();
94      }
95  
96      private Map<E, String> _map;
97  
98  }