1 // ========================================================================
2 // Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd.
3 // ------------------------------------------------------------------------
4 // All rights reserved. This program and the accompanying materials
5 // are made available under the terms of the Eclipse Public License v1.0
6 // and Apache License v2.0 which accompanies this distribution.
7 // The Eclipse Public License is available at
8 // http://www.eclipse.org/legal/epl-v10.html
9 // The Apache License v2.0 is available at
10 // http://www.opensource.org/licenses/apache2.0.php
11 // You may elect to redistribute this code under either of these licenses.
12 // ========================================================================
13
14 package org.eclipse.jetty.util.ajax;
15
16 import java.lang.reflect.Method;
17 import java.util.Map;
18
19 import org.eclipse.jetty.util.Loader;
20 import org.eclipse.jetty.util.ajax.JSON.Output;
21 import org.eclipse.jetty.util.log.Log;
22
23 /* ------------------------------------------------------------ */
24 /**
25 * Convert an {@link Enum} to JSON.
26 * If fromJSON is true in the constructor, the JSON generated will
27 * be of the form {class="com.acme.TrafficLight",value="Green"}
28 * If fromJSON is false, then only the string value of the enum is generated.
29 *
30 *
31 */
32 public class JSONEnumConvertor implements JSON.Convertor
33 {
34 private boolean _fromJSON;
35 private Method _valueOf;
36 {
37 try
38 {
39 Class e = Loader.loadClass(getClass(),"java.lang.Enum");
40 _valueOf=e.getMethod("valueOf",new Class[]{Class.class,String.class});
41 }
42 catch(Exception e)
43 {
44 throw new RuntimeException("!Enums",e);
45 }
46 }
47
48 public JSONEnumConvertor()
49 {
50 this(false);
51 }
52
53 public JSONEnumConvertor(boolean fromJSON)
54 {
55 _fromJSON=fromJSON;
56 }
57
58 public Object fromJSON(Map map)
59 {
60 if (!_fromJSON)
61 throw new UnsupportedOperationException();
62 try
63 {
64 Class c=Loader.loadClass(getClass(),(String)map.get("class"));
65 return _valueOf.invoke(null,new Object[]{c,map.get("value")});
66 }
67 catch(Exception e)
68 {
69 Log.warn(e);
70 }
71 return null;
72 }
73
74 public void toJSON(Object obj, Output out)
75 {
76 if (_fromJSON)
77 {
78 out.addClass(obj.getClass());
79 out.add("value",obj.toString());
80 }
81 else
82 {
83 out.add(obj.toString());
84 }
85 }
86
87 }