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Java > Open Source Codes > org > jboss > xb > util > NoopMap


1 /*
2   * JBoss, Home of Professional Open Source
3   * Copyright 2005, JBoss Inc., and individual contributors as indicated
4   * by the @authors tag. See the copyright.txt in the distribution for a
5   * full listing of individual contributors.
6   *
7   * This is free software; you can redistribute it and/or modify it
8   * under the terms of the GNU Lesser General Public License as
9   * published by the Free Software Foundation; either version 2.1 of
10   * the License, or (at your option) any later version.
11   *
12   * This software is distributed in the hope that it will be useful,
13   * but WITHOUT ANY WARRANTY; without even the implied warranty of
14   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15   * Lesser General Public License for more details.
16   *
17   * You should have received a copy of the GNU Lesser General Public
18   * License along with this software; if not, write to the Free
19   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
21   */
22 package org.jboss.xb.util;
23
24 import java.util.AbstractMap JavaDoc;
25 import java.util.Collection JavaDoc;
26 import java.util.Collections JavaDoc;
27 import java.util.Map JavaDoc;
28 import java.util.Set JavaDoc;
29
30 /**
31  * @author <a HREF="mailto:alex@jboss.org">Alexey Loubyansky</a>
32  * @version <tt>$Revision: $</tt>
33  */
34 public class NoopMap
35    extends AbstractMap JavaDoc
36 {
37    public static final Map JavaDoc INSTANCE = new NoopMap();
38
39    public Object JavaDoc put(Object JavaDoc key, Object JavaDoc value)
40    {
41       return null;
42    }
43
44    public int size()
45    {
46       return 0;
47    }
48
49    public boolean isEmpty()
50    {
51       return true;
52    }
53
54    public boolean containsKey(Object JavaDoc key)
55    {
56       return false;
57    }
58
59    public boolean containsValue(Object JavaDoc value)
60    {
61       return false;
62    }
63
64    public Object JavaDoc get(Object JavaDoc key)
65    {
66       return null;
67    }
68
69    public Set JavaDoc keySet()
70    {
71       return Collections.EMPTY_SET;
72    }
73
74    public Collection JavaDoc values()
75    {
76       return Collections.EMPTY_SET;
77    }
78
79    public Set JavaDoc entrySet()
80    {
81       return Collections.EMPTY_SET;
82    }
83
84    public boolean equals(Object JavaDoc o)
85    {
86       return (o instanceof Map JavaDoc) && ((Map JavaDoc)o).size() == 0;
87    }
88
89    public int hashCode()
90    {
91       return 0;
92    }
93 }
94
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