1 package org
.argeo
.server
.json
;
3 import java
.io
.IOException
;
4 import java
.io
.StringWriter
;
5 import java
.util
.ArrayList
;
8 import org
.apache
.commons
.logging
.Log
;
9 import org
.apache
.commons
.logging
.LogFactory
;
10 import org
.argeo
.ArgeoException
;
11 import org
.codehaus
.jackson
.JsonFactory
;
12 import org
.codehaus
.jackson
.JsonGenerator
;
13 import org
.codehaus
.jackson
.JsonNode
;
14 import org
.codehaus
.jackson
.JsonParser
;
15 import org
.codehaus
.jackson
.JsonProcessingException
;
16 import org
.codehaus
.jackson
.ObjectCodec
;
17 import org
.codehaus
.jackson
.map
.DeserializationContext
;
18 import org
.codehaus
.jackson
.map
.JsonDeserializer
;
19 import org
.codehaus
.jackson
.map
.ObjectMapper
;
21 public class GenericJsonDeserializer
<T
> extends JsonDeserializer
<T
> {
22 private final static Log log
= LogFactory
23 .getLog(GenericJsonDeserializer
.class);
25 private JsonFactory jsonFactory
= new JsonFactory();
26 private ObjectCodec objectCodec
= new ObjectMapper();
27 private JsonObjectFactory defaultObjectFactory
= new JsonObjectFactoryImpl();
29 private String typeField
= "type";
31 private List
<JsonObjectFactory
> objectFactories
= new ArrayList
<JsonObjectFactory
>();
33 @SuppressWarnings("unchecked")
35 public T
deserialize(JsonParser parser
, DeserializationContext ctxt
)
36 throws IOException
, JsonProcessingException
{
37 // first read as Json DOM in order to extract the type
38 // TODO: optimize with streaming API
39 JsonNode root
= parser
.readValueAsTree();
40 String type
= root
.get(typeField
).getTextValue();
42 // Write it back as a string
43 StringWriter writer
= new StringWriter();
44 JsonGenerator generator
= jsonFactory
.createJsonGenerator(writer
);
45 generator
.setCodec(objectCodec
);
46 generator
.writeTree(root
);
47 String str
= writer
.toString();
49 if (log
.isTraceEnabled())
50 log
.debug("Deserialize object of type=" + type
+ ", str=" + str
);
52 JsonObjectFactory objectFactory
= null;
53 jofs
: for (JsonObjectFactory jof
: objectFactories
) {
54 if (jof
.supports(type
)) {
60 if (objectFactory
== null)
61 objectFactory
= defaultObjectFactory
;
63 if (objectFactory
== null || !objectFactory
.supports(type
))
64 throw new ArgeoException(
65 "Cannot find JSON object factory for type " + type
);
67 return (T
) objectFactory
.readValue(type
, str
);
70 public void setTypeField(String typeField
) {
71 this.typeField
= typeField
;
74 public void setObjectFactories(List
<JsonObjectFactory
> objectFactories
) {
75 this.objectFactories
= objectFactories
;
78 public List
<JsonObjectFactory
> getObjectFactories() {
79 return objectFactories
;