1   /**
2    * Copyright (c) 2000-2008 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.util;
24  
25  import com.liferay.portal.kernel.util.StringPool;
26  
27  import java.util.AbstractSet;
28  import java.util.Iterator;
29  import java.util.Map;
30  import java.util.Set;
31  import java.util.concurrent.ConcurrentHashMap;
32  
33  /**
34   * <a href="ConcurrentHashSet.java.html"><b><i>View Source</i></b></a>
35   *
36   * @author Brian Wing Shun Chan
37   *
38   */
39  public class ConcurrentHashSet<E> extends AbstractSet<E> {
40  
41      public ConcurrentHashSet() {
42          _map = new ConcurrentHashMap<E, String>();
43      }
44  
45      public ConcurrentHashSet(int capacity) {
46          _map = new ConcurrentHashMap<E, String>(capacity);
47      }
48  
49      public ConcurrentHashSet(Set<E> set) {
50          Iterator<E> itr = set.iterator();
51  
52          while (itr.hasNext()) {
53              E e = itr.next();
54  
55              _map.put(e, StringPool.BLANK);
56          }
57      }
58  
59      public boolean add(E e) {
60          if (_map.put(e, StringPool.BLANK) == null) {
61              return true;
62          }
63          else {
64              return false;
65          }
66      }
67  
68      public void clear() {
69          _map.clear();
70      }
71  
72      public boolean contains(Object obj) {
73          if (_map.containsKey(obj)) {
74              return true;
75          }
76          else {
77              return false;
78          }
79      }
80  
81      public Iterator<E> iterator() {
82          return _map.keySet().iterator();
83      }
84  
85      public boolean remove(Object obj) {
86          if (_map.remove(obj) == null) {
87              return false;
88          }
89          else {
90              return true;
91          }
92      }
93  
94      public int size() {
95          return _map.size();
96      }
97  
98      private Map<E, String> _map;
99  
100 }