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1   //========================================================================
2   //Copyright 2004-2008 Mort Bay Consulting Pty. Ltd.
3   //------------------------------------------------------------------------
4   //Licensed under the Apache License, Version 2.0 (the "License");
5   //you may not use this file except in compliance with the License.
6   //You may obtain a copy of the License at 
7   //http://www.apache.org/licenses/LICENSE-2.0
8   //Unless required by applicable law or agreed to in writing, software
9   //distributed under the License is distributed on an "AS IS" BASIS,
10  //WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11  //See the License for the specific language governing permissions and
12  //limitations under the License.
13  //========================================================================
14  
15  package org.mortbay.util.ajax;
16  
17  import java.lang.reflect.Method;
18  import java.lang.reflect.Modifier;
19  import java.util.Arrays;
20  import java.util.HashSet;
21  import java.util.Map;
22  import java.util.Set;
23  
24  import org.mortbay.util.ajax.JSON.Output;
25  
26  /* ------------------------------------------------------------ */
27  /**
28   * Convert an Object to JSON using reflection on getters methods.
29   * 
30   * @author gregw
31   *
32   */
33  public class JSONObjectConvertor implements JSON.Convertor
34  {
35      private boolean _fromJSON;
36      private Set _excluded=null;
37  
38      public JSONObjectConvertor()
39      {
40          _fromJSON=false;
41      }
42      
43      public JSONObjectConvertor(boolean fromJSON)
44      {
45          _fromJSON=fromJSON;
46      }
47      
48      /* ------------------------------------------------------------ */
49      /**
50       * @param fromJSON
51       * @param excluded An array of field names to exclude from the conversion
52       */
53      public JSONObjectConvertor(boolean fromJSON,String[] excluded)
54      {
55          _fromJSON=fromJSON;
56          if (excluded!=null)
57              _excluded=new HashSet(Arrays.asList(excluded));
58      }
59  
60      public Object fromJSON(Map map)
61      {
62          if (_fromJSON)
63              throw new UnsupportedOperationException();
64          return map;
65      }
66  
67      public void toJSON(Object obj, Output out)
68      {
69          try
70          {
71              Class c=obj.getClass();
72  
73              if (_fromJSON)
74                  out.addClass(obj.getClass());
75  
76              Method[] methods = obj.getClass().getMethods();
77  
78              for (int i=0;i<methods.length;i++)
79              {
80                  Method m=methods[i];
81                  if (!Modifier.isStatic(m.getModifiers()) &&  
82                          m.getParameterTypes().length==0 && 
83                          m.getReturnType()!=null &&
84                          m.getDeclaringClass()!=Object.class)
85                  {
86                      String name=m.getName();
87                      if (name.startsWith("is"))
88                          name=name.substring(2,3).toLowerCase()+name.substring(3);
89                      else if (name.startsWith("get"))
90                          name=name.substring(3,4).toLowerCase()+name.substring(4);
91                      else
92                          continue;
93  
94                      if (includeField(name,obj,m))
95                          out.add(name, m.invoke(obj,(Object[])null));
96                  }
97              }
98          } 
99          catch (Throwable e)
100         {
101             throw new RuntimeException("Illegal argument", e);
102         }
103     }
104     
105     protected boolean includeField(String name, Object o, Method m)
106     {
107         return _excluded==null || !_excluded.contains(name);
108     }
109 
110 }