X-Git-Url: http://git.ieval.ro/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcom%2Fgoogle%2Fgson%2FJsonDeserializer.java;fp=src%2Fcom%2Fgoogle%2Fgson%2FJsonDeserializer.java;h=0589eb284085c90c31ed4dcaefb13775c9626b6d;hb=cfd903b6b5113fa28991db19bf98d0340ae709a4;hp=0000000000000000000000000000000000000000;hpb=819197b2305a94ab4924c5ae37a3fad762078448;p=unical.git diff --git a/src/com/google/gson/JsonDeserializer.java b/src/com/google/gson/JsonDeserializer.java new file mode 100644 index 0000000..0589eb2 --- /dev/null +++ b/src/com/google/gson/JsonDeserializer.java @@ -0,0 +1,91 @@ +/* + * Copyright (C) 2008 Google Inc. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package com.google.gson; + +import java.lang.reflect.Type; + +/** + *
Interface representing a custom deserializer for Json. You should write a custom + * deserializer, if you are not happy with the default deserialization done by Gson. You will + * also need to register this deserializer through + * {@link GsonBuilder#registerTypeAdapter(Type, Object)}.
+ * + *Let us look at example where defining a deserializer will be useful. The {@code Id} class + * defined below has two fields: {@code clazz} and {@code value}.
+ * + *+ * public class Id<T> { + * private final Class<T> clazz; + * private final long value; + * public Id(Class<T> clazz, long value) { + * this.clazz = clazz; + * this.value = value; + * } + * public long getValue() { + * return value; + * } + * } + *+ * + *
The default deserialization of {@code Id(com.foo.MyObject.class, 20L)} will require the
+ * Json string to be {"clazz":com.foo.MyObject,"value":20}
. Suppose, you already know
+ * the type of the field that the {@code Id} will be deserialized into, and hence just want to
+ * deserialize it from a Json string {@code 20}. You can achieve that by writing a custom
+ * deserializer:
+ * class IdDeserializer implements JsonDeserializer<Id>() { + * public Id deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) + * throws JsonParseException { + * return new Id((Class)typeOfT, id.getValue()); + * } + *+ * + *
You will also need to register {@code IdDeserializer} with Gson as follows:
+ * + *+ * Gson gson = new GsonBuilder().registerTypeAdapter(Id.class, new IdDeserializer()).create(); + *+ * + *
New applications should prefer {@link TypeAdapter}, whose streaming API
+ * is more efficient than this interface's tree API.
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ *
+ * @param In the implementation of this call-back method, you should consider invoking
+ * {@link JsonDeserializationContext#deserialize(JsonElement, Type)} method to create objects
+ * for any non-trivial field of the returned object. However, you should never invoke it on the
+ * the same type passing {@code json} since that will cause an infinite loop (Gson will call your
+ * call-back method again).
+ *
+ * @param json The Json data being deserialized
+ * @param typeOfT The type of the Object to deserialize to
+ * @return a deserialized object of the specified type typeOfT which is a subclass of {@code T}
+ * @throws JsonParseException if json is not in the expected format of {@code typeofT}
+ */
+ public T deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+ throws JsonParseException;
+}