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1    package org.alfresco.maven.plugin.amp.util;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.util.AbstractMap;
23  import java.util.Collections;
24  import java.util.Map;
25  import java.util.Set;
26  
27  /***
28   * @version $Id: CompositeMap.java 565036 2007-08-12 10:26:14Z snicoll $
29   * @todo merge with resources/assembly plugin
30   */
31  public class CompositeMap
32      extends AbstractMap
33  {
34      private Map recessive;
35  
36      private Map dominant;
37  
38      public CompositeMap( Map dominant, Map recessive )
39      {
40          this.dominant = Collections.unmodifiableMap( dominant );
41  
42          this.recessive = Collections.unmodifiableMap( recessive );
43      }
44  
45      public synchronized Object get( Object key )
46      {
47          Object value = dominant.get( key );
48  
49          if ( value == null )
50          {
51              value = recessive.get( key );
52          }
53  
54          return value;
55      }
56  
57      public Set entrySet()
58      {
59          throw new UnsupportedOperationException( "Cannot enumerate properties in a composite map" );
60      }
61  }