1 //
2 // ========================================================================
3 // Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.util.ajax;
20
21 import java.lang.reflect.Method;
22 import java.util.Map;
23
24 import org.eclipse.jetty.util.Loader;
25 import org.eclipse.jetty.util.ajax.JSON.Output;
26 import org.eclipse.jetty.util.log.Log;
27 import org.eclipse.jetty.util.log.Logger;
28
29 /* ------------------------------------------------------------ */
30 /**
31 * Convert an {@link Enum} to JSON.
32 * If fromJSON is true in the constructor, the JSON generated will
33 * be of the form {class="com.acme.TrafficLight",value="Green"}
34 * If fromJSON is false, then only the string value of the enum is generated.
35 *
36 *
37 */
38 public class JSONEnumConvertor implements JSON.Convertor
39 {
40 private static final Logger LOG = Log.getLogger(JSONEnumConvertor.class);
41 private boolean _fromJSON;
42 private Method _valueOf;
43 {
44 try
45 {
46 Class<?> e = Loader.loadClass(getClass(),"java.lang.Enum");
47 _valueOf=e.getMethod("valueOf",Class.class,String.class);
48 }
49 catch(Exception e)
50 {
51 throw new RuntimeException("!Enums",e);
52 }
53 }
54
55 public JSONEnumConvertor()
56 {
57 this(false);
58 }
59
60 public JSONEnumConvertor(boolean fromJSON)
61 {
62 _fromJSON=fromJSON;
63 }
64
65 public Object fromJSON(Map map)
66 {
67 if (!_fromJSON)
68 throw new UnsupportedOperationException();
69 try
70 {
71 Class c=Loader.loadClass(getClass(),(String)map.get("class"));
72 return _valueOf.invoke(null,c,map.get("value"));
73 }
74 catch(Exception e)
75 {
76 LOG.warn(e);
77 }
78 return null;
79 }
80
81 public void toJSON(Object obj, Output out)
82 {
83 if (_fromJSON)
84 {
85 out.addClass(obj.getClass());
86 out.add("value",((Enum)obj).name());
87 }
88 else
89 {
90 out.add(((Enum)obj).name());
91 }
92 }
93 }