1   /**
2    * Copyright (c) 2000-2009 Liferay, Inc. All rights reserved.
3    *
4    * The contents of this file are subject to the terms of the Liferay Enterprise
5    * Subscription License ("License"). You may not use this file except in
6    * compliance with the License. You can obtain a copy of the License by
7    * contacting Liferay, Inc. See the License for the specific language governing
8    * permissions and limitations under the License, including but not limited to
9    * distribution rights of the Software.
10   *
11   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
12   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
13   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
14   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
15   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
16   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
17   * SOFTWARE.
18   */
19  
20  package com.liferay.portal.kernel.util;
21  
22  import java.util.AbstractSet;
23  import java.util.Iterator;
24  import java.util.Map;
25  import java.util.Set;
26  import java.util.concurrent.ConcurrentHashMap;
27  
28  /**
29   * <a href="ConcurrentHashSet.java.html"><b><i>View Source</i></b></a>
30   *
31   * @author Brian Wing Shun Chan
32   *
33   */
34  public class ConcurrentHashSet<E> extends AbstractSet<E> {
35  
36      public ConcurrentHashSet() {
37          _map = new ConcurrentHashMap<E, String>();
38      }
39  
40      public ConcurrentHashSet(int capacity) {
41          _map = new ConcurrentHashMap<E, String>(capacity);
42      }
43  
44      public ConcurrentHashSet(Set<E> set) {
45          Iterator<E> itr = set.iterator();
46  
47          while (itr.hasNext()) {
48              E e = itr.next();
49  
50              _map.put(e, StringPool.BLANK);
51          }
52      }
53  
54      public boolean add(E e) {
55          if (_map.put(e, StringPool.BLANK) == null) {
56              return true;
57          }
58          else {
59              return false;
60          }
61      }
62  
63      public void clear() {
64          _map.clear();
65      }
66  
67      public boolean contains(Object obj) {
68          if (_map.containsKey(obj)) {
69              return true;
70          }
71          else {
72              return false;
73          }
74      }
75  
76      public Iterator<E> iterator() {
77          return _map.keySet().iterator();
78      }
79  
80      public boolean remove(Object obj) {
81          if (_map.remove(obj) == null) {
82              return false;
83          }
84          else {
85              return true;
86          }
87      }
88  
89      public int size() {
90          return _map.size();
91      }
92  
93      private Map<E, String> _map;
94  
95  }