2 * Copyright (C) 2010 Mathieu Baudier <mbaudier@argeo.org>
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
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package org
.argeo
.server
.json
;
19 import java
.io
.IOException
;
20 import java
.io
.StringWriter
;
21 import java
.util
.ArrayList
;
22 import java
.util
.List
;
24 import org
.apache
.commons
.logging
.Log
;
25 import org
.apache
.commons
.logging
.LogFactory
;
26 import org
.argeo
.ArgeoException
;
27 import org
.codehaus
.jackson
.JsonFactory
;
28 import org
.codehaus
.jackson
.JsonGenerator
;
29 import org
.codehaus
.jackson
.JsonNode
;
30 import org
.codehaus
.jackson
.JsonParser
;
31 import org
.codehaus
.jackson
.JsonProcessingException
;
32 import org
.codehaus
.jackson
.ObjectCodec
;
33 import org
.codehaus
.jackson
.map
.DeserializationContext
;
34 import org
.codehaus
.jackson
.map
.JsonDeserializer
;
35 import org
.codehaus
.jackson
.map
.ObjectMapper
;
37 public class GenericJsonDeserializer
<T
> extends JsonDeserializer
<T
> {
38 private final static Log log
= LogFactory
39 .getLog(GenericJsonDeserializer
.class);
41 private JsonFactory jsonFactory
= new JsonFactory();
42 private ObjectCodec objectCodec
= new ObjectMapper();
43 private JsonObjectFactory defaultObjectFactory
= new JsonObjectFactoryImpl();
45 private String typeField
= "type";
47 private List
<JsonObjectFactory
> objectFactories
= new ArrayList
<JsonObjectFactory
>();
49 @SuppressWarnings("unchecked")
51 public T
deserialize(JsonParser parser
, DeserializationContext ctxt
)
52 throws IOException
, JsonProcessingException
{
53 // first read as Json DOM in order to extract the type
54 // TODO: optimize with streaming API
55 JsonNode root
= parser
.readValueAsTree();
56 String type
= root
.get(typeField
).getTextValue();
58 // Write it back as a string
59 StringWriter writer
= new StringWriter();
60 JsonGenerator generator
= jsonFactory
.createJsonGenerator(writer
);
61 generator
.setCodec(objectCodec
);
62 generator
.writeTree(root
);
63 String str
= writer
.toString();
65 if (log
.isTraceEnabled())
66 log
.debug("Deserialize object of type=" + type
+ ", str=" + str
);
68 JsonObjectFactory objectFactory
= null;
69 jofs
: for (JsonObjectFactory jof
: objectFactories
) {
70 if (jof
.supports(type
)) {
76 if (objectFactory
== null)
77 objectFactory
= defaultObjectFactory
;
79 if (objectFactory
== null || !objectFactory
.supports(type
))
80 throw new ArgeoException(
81 "Cannot find JSON object factory for type " + type
);
83 return (T
) objectFactory
.readValue(type
, str
);
86 public void setTypeField(String typeField
) {
87 this.typeField
= typeField
;
90 public void setObjectFactories(List
<JsonObjectFactory
> objectFactories
) {
91 this.objectFactories
= objectFactories
;
94 public List
<JsonObjectFactory
> getObjectFactories() {
95 return objectFactories
;