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1   /*
2    * $Id: MapLookup.java 7963 2007-08-21 08:53:15Z dirk.olmes $
3    * --------------------------------------------------------------------------------------
4    * Copyright (c) MuleSource, Inc.  All rights reserved.  http://www.mulesource.com
5    *
6    * The software in this package is published under the terms of the CPAL v1.0
7    * license, a copy of which has been included with this distribution in the
8    * LICENSE.txt file.
9    */
10  
11  package org.mule.transformers.simple;
12  
13  import org.mule.config.i18n.MessageFactory;
14  import org.mule.transformers.AbstractTransformer;
15  import org.mule.umo.transformer.TransformerException;
16  
17  import java.util.Map;
18  
19  /**
20   * <code>MapLookup</code> looks up and returns an object from a Map based on a key.
21   */
22  
23  public class MapLookup extends AbstractTransformer
24  {
25  
26      protected volatile Object key;
27  
28      public MapLookup()
29      {
30          registerSourceType(Map.class);
31          setReturnClass(Object.class);
32      }
33  
34      public Object doTransform(Object src, String encoding) throws TransformerException
35      {
36          if (src instanceof Map)
37          {
38              if (key != null)
39              {
40                  return ((Map) src).get(key);
41              }
42              else
43              {
44                  throw new TransformerException(MessageFactory
45                          .createStaticMessage("Property 'key' must be set in order to use this transformer."));
46              }
47          }
48          else
49          {
50              throw new TransformerException(MessageFactory
51                      .createStaticMessage("Message to transform must be of type java.util.Map"));
52          }
53      }
54  
55      public Object getKey()
56      {
57          return key;
58      }
59  
60      public void setKey(Object key)
61      {
62          this.key = key;
63      }
64  
65  }