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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.configuration;
19  
20  import java.util.AbstractMap;
21  import java.util.AbstractSet;
22  import java.util.Iterator;
23  import java.util.Map;
24  import java.util.Set;
25  
26  /***
27   * <p>The <code>ConfigurationMap</code> wraps a
28   * configuration-collection
29   * {@link org.apache.commons.configuration.Configuration}
30   * instance to provide a <code>Map</code> interface.</p>
31   *
32   * <p><em>Note:</em> This implementation is incomplete.</p>
33   *
34   * @author <a href="mailto:ricardo.gladwell@btinternet.com">Ricardo Gladwell</a>
35   * @version $Revision: 492216 $, $Date: 2007-01-03 17:51:24 +0100 (Mi, 03 Jan 2007) $
36   * @since 1.0
37   */
38  public class ConfigurationMap extends AbstractMap
39  {
40      /***
41       * The <code>Configuration</code> wrapped by this class.
42       */
43      private Configuration configuration;
44  
45      /***
46       * Creates a new instance of a <code>ConfigurationMap</code>
47       * that wraps the specified <code>Configuration</code>
48       * instance.
49       * @param configuration <code>Configuration</code>
50       * instance.
51       */
52      public ConfigurationMap(Configuration configuration)
53      {
54          this.configuration = configuration;
55      }
56  
57      /***
58       * Returns the wrapped <code>Configuration</code> object.
59       *
60       * @return the wrapped configuration
61       * @since 1.2
62       */
63      public Configuration getConfiguration()
64      {
65          return configuration;
66      }
67  
68      /***
69       * Returns a set with the entries contained in this configuration-based map.
70       *
71       * @return a set with the contained entries
72       * @see java.util.Map#entrySet()
73       */
74      public Set entrySet()
75      {
76          return new ConfigurationSet(configuration);
77      }
78  
79      /***
80       * Stores the value for the specified key. The value is stored in the
81       * underlying configuration.
82       *
83       * @param key the key (will be converted to a string)
84       * @param value the value
85       * @return the old value of this key or <b>null</b> if it is new
86       * @see java.util.Map#put(java.lang.Object, java.lang.Object)
87       */
88      public Object put(Object key, Object value)
89      {
90          String strKey = String.valueOf(key);
91          Object old = configuration.getProperty(strKey);
92          configuration.setProperty(strKey, value);
93          return old;
94      }
95  
96      /***
97       * Returns the value of the specified key. The key is converted to a string
98       * and then passed to the underlying configuration.
99       *
100      * @param key the key
101      * @return the value of this key
102      * @see java.util.Map#get(java.lang.Object)
103      */
104     public Object get(Object key)
105     {
106         return configuration.getProperty(String.valueOf(key));
107     }
108 
109     /***
110      * Set of entries in the map.
111      */
112     static class ConfigurationSet extends AbstractSet
113     {
114         /*** The configuration mapped to this entry set. */
115         private Configuration configuration;
116 
117         /***
118          * A Map entry in the ConfigurationMap.
119          */
120         private final class Entry implements Map.Entry
121         {
122             /*** The key of the map entry. */
123             private Object key;
124 
125             private Entry(Object key)
126             {
127                 this.key = key;
128             }
129 
130             public Object getKey()
131             {
132                 return key;
133             }
134 
135             public Object getValue()
136             {
137                 return configuration.getProperty((String) key);
138             }
139 
140             public Object setValue(Object value)
141             {
142                 Object old = getValue();
143                 configuration.setProperty((String) key, value);
144                 return old;
145             }
146         }
147 
148         /***
149          * Iterator over the entries in the ConfigurationMap.
150          */
151         private final class ConfigurationSetIterator implements Iterator
152         {
153             /*** An iterator over the keys in the configuration. */
154             private Iterator keys;
155 
156             private ConfigurationSetIterator()
157             {
158                 keys = configuration.getKeys();
159             }
160 
161             public boolean hasNext()
162             {
163                 return keys.hasNext();
164             }
165 
166             public Object next()
167             {
168                 return new Entry(keys.next());
169             }
170 
171             public void remove()
172             {
173                 keys.remove();
174             }
175         }
176 
177         ConfigurationSet(Configuration configuration)
178         {
179             this.configuration = configuration;
180         }
181 
182         /***
183          * @see java.util.Collection#size()
184          */
185         public int size()
186         {
187             // Ouch. Now _that_ one is expensive...
188             int count = 0;
189             for (Iterator iterator = configuration.getKeys(); iterator.hasNext();)
190             {
191                 iterator.next();
192                 count++;
193             }
194             return count;
195         }
196 
197         /***
198          * @see java.util.Collection#iterator()
199          */
200         public Iterator iterator()
201         {
202             return new ConfigurationSetIterator();
203         }
204     }
205 }