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1   /*
2    $Id: SpreadMap.java,v 1.2 2005/07/23 12:09:47 phk Exp $
3   
4    Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
5   
6    Redistribution and use of this software and associated documentation
7    ("Software"), with or without modification, are permitted provided
8    that the following conditions are met:
9   
10   1. Redistributions of source code must retain copyright
11      statements and notices.  Redistributions must also contain a
12      copy of this document.
13  
14   2. Redistributions in binary form must reproduce the
15      above copyright notice, this list of conditions and the
16      following disclaimer in the documentation and/or other
17      materials provided with the distribution.
18  
19   3. The name "groovy" must not be used to endorse or promote
20      products derived from this Software without prior written
21      permission of The Codehaus.  For written permission,
22      please contact info@codehaus.org.
23  
24   4. Products derived from this Software may not be called "groovy"
25      nor may "groovy" appear in their names without prior written
26      permission of The Codehaus. "groovy" is a registered
27      trademark of The Codehaus.
28  
29   5. Due credit should be given to The Codehaus -
30      http://groovy.codehaus.org/
31  
32   THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
33   ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
34   NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
35   FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
36   THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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41   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43   OF THE POSSIBILITY OF SUCH DAMAGE.
44  
45   */
46  package groovy.lang;
47  
48  import java.util.HashMap;
49  import java.util.Map;
50  import java.util.Iterator;
51  
52  import org.codehaus.groovy.runtime.InvokerHelper;
53  
54  /***
55   * Represents a spreadable map which extends java.util.HashMap.
56   * 
57   * @author Pilho Kim
58   * @version $Revision: 1.2 $
59   */
60  public class SpreadMap extends HashMap {
61  
62      private Map mapData;
63      private int hashCode;
64  
65      public SpreadMap(Object[] values) {
66          mapData = new HashMap(values.length / 2);
67          int i = 0;
68          while (i < values.length) {
69             mapData.put(values[i++], values[i++]);
70          }
71      }
72  
73      public SpreadMap(Map map) {
74          this.mapData = map;
75      }
76  
77      public Object get(Object obj) {
78          return mapData.get(obj);
79      }
80  
81      public Object put(Object key, Object value) {
82          throw new RuntimeException("SpreadMap: " + this + " is an immutable map, and so ("
83                                     + key + ": " + value + ") cannot be added.");
84      }
85  
86      public Object remove(Object key) {
87          throw new RuntimeException("SpreadMap: " + this + " is an immutable map, and so the key ("
88                                     + key + ") cannot be deleteded.");
89      }
90  
91      public void putAll(Map t) {
92          throw new RuntimeException("SpreadMap: " + this + " is an immutable map, and so the map ("
93                                     + t + ") cannot be put in this spreadMap.");
94      }
95  
96      public int size() {
97          return mapData.keySet().size();
98      }
99  
100     public boolean equals(Object that) {
101         if (that instanceof SpreadMap) {
102             return equals((SpreadMap) that);
103         }
104         return false;
105     }
106 
107     public boolean equals(SpreadMap that) {
108         if (this == null && that == null)
109             return true;
110         else if (this != null && that == null)
111             return false;
112         else if (this == null && that != null)
113             return false;
114 
115         if (size() == that.size()) {
116             SpreadMap other = (SpreadMap) that;
117             Iterator iter = mapData.keySet().iterator();
118             for (; iter.hasNext(); ) {
119                 Object key = iter.next();
120                 if (! InvokerHelper.compareEqual(get(key), other.get(key)) ) {
121                     return false;
122                 }
123             }
124             return true;
125         }
126         return false;
127     }
128 
129 
130     public int hashCode() {
131         if (hashCode == 0) {
132             Iterator iter = mapData.keySet().iterator();
133             for (; iter.hasNext(); ) {
134                 Object key = iter.next();
135                 int hash = (key != null) ? key.hashCode() : 0xbabe;
136                 hashCode ^= hash;
137             }
138         }
139         return hashCode;
140     }
141 
142     /***
143      * Returns the string expression of <code>this</code>.
144      *
145      * @return the string expression of <code>this</code>
146      */
147     public String toString() {
148         if (mapData.isEmpty()) {
149             return "*:[:]";
150         }
151         StringBuffer buff = new StringBuffer("*:[");
152         Iterator iter = mapData.keySet().iterator();
153         for (; iter.hasNext(); ) {
154             Object key = iter.next();
155             buff.append(key + ":" + mapData.get(key));
156             if (iter.hasNext())
157                 buff.append(", ");
158         }
159         buff.append("]");
160         return buff.toString();
161     }
162 }