Commit | Line | Data |
---|---|---|
cfd903b6 MG |
1 | /* |
2 | * Copyright (C) 2011 Google Inc. | |
3 | * | |
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 | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
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. | |
15 | */ | |
16 | ||
17 | package com.google.gson.internal.bind; | |
18 | ||
19 | import com.google.gson.Gson; | |
20 | import com.google.gson.TypeAdapter; | |
21 | import com.google.gson.TypeAdapterFactory; | |
22 | import com.google.gson.internal.$Gson$Types; | |
23 | import com.google.gson.internal.ConstructorConstructor; | |
24 | import com.google.gson.internal.ObjectConstructor; | |
25 | import com.google.gson.reflect.TypeToken; | |
26 | import com.google.gson.stream.JsonReader; | |
27 | import com.google.gson.stream.JsonToken; | |
28 | import com.google.gson.stream.JsonWriter; | |
29 | import java.io.IOException; | |
30 | import java.lang.reflect.Type; | |
31 | import java.util.Collection; | |
32 | ||
33 | /** | |
34 | * Adapt a homogeneous collection of objects. | |
35 | */ | |
36 | public final class CollectionTypeAdapterFactory implements TypeAdapterFactory { | |
37 | private final ConstructorConstructor constructorConstructor; | |
38 | ||
39 | public CollectionTypeAdapterFactory(ConstructorConstructor constructorConstructor) { | |
40 | this.constructorConstructor = constructorConstructor; | |
41 | } | |
42 | ||
43 | public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) { | |
44 | Type type = typeToken.getType(); | |
45 | ||
46 | Class<? super T> rawType = typeToken.getRawType(); | |
47 | if (!Collection.class.isAssignableFrom(rawType)) { | |
48 | return null; | |
49 | } | |
50 | ||
51 | Type elementType = $Gson$Types.getCollectionElementType(type, rawType); | |
52 | TypeAdapter<?> elementTypeAdapter = gson.getAdapter(TypeToken.get(elementType)); | |
53 | ObjectConstructor<T> constructor = constructorConstructor.get(typeToken); | |
54 | ||
55 | @SuppressWarnings({"unchecked", "rawtypes"}) // create() doesn't define a type parameter | |
56 | TypeAdapter<T> result = new Adapter(gson, elementType, elementTypeAdapter, constructor); | |
57 | return result; | |
58 | } | |
59 | ||
60 | private static final class Adapter<E> extends TypeAdapter<Collection<E>> { | |
61 | private final TypeAdapter<E> elementTypeAdapter; | |
62 | private final ObjectConstructor<? extends Collection<E>> constructor; | |
63 | ||
64 | public Adapter(Gson context, Type elementType, | |
65 | TypeAdapter<E> elementTypeAdapter, | |
66 | ObjectConstructor<? extends Collection<E>> constructor) { | |
67 | this.elementTypeAdapter = | |
68 | new TypeAdapterRuntimeTypeWrapper<E>(context, elementTypeAdapter, elementType); | |
69 | this.constructor = constructor; | |
70 | } | |
71 | ||
72 | public Collection<E> read(JsonReader in) throws IOException { | |
73 | if (in.peek() == JsonToken.NULL) { | |
74 | in.nextNull(); | |
75 | return null; | |
76 | } | |
77 | ||
78 | Collection<E> collection = constructor.construct(); | |
79 | in.beginArray(); | |
80 | while (in.hasNext()) { | |
81 | E instance = elementTypeAdapter.read(in); | |
82 | collection.add(instance); | |
83 | } | |
84 | in.endArray(); | |
85 | return collection; | |
86 | } | |
87 | ||
88 | public void write(JsonWriter out, Collection<E> collection) throws IOException { | |
89 | if (collection == null) { | |
90 | out.nullValue(); | |
91 | return; | |
92 | } | |
93 | ||
94 | out.beginArray(); | |
95 | for (E element : collection) { | |
96 | elementTypeAdapter.write(out, element); | |
97 | } | |
98 | out.endArray(); | |
99 | } | |
100 | } | |
101 | } |