1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/*
* Copyright (C) 2011 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.internal.bind;
import com.google.gson.Gson;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.internal.$Gson$Preconditions;
import com.google.gson.internal.Streams;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.lang.reflect.Type;
/**
* Adapts a Gson 1.x tree-style adapter as a streaming TypeAdapter. Since the
* tree adapter may be serialization-only or deserialization-only, this class
* has a facility to lookup a delegate type adapter on demand.
*/
public final class TreeTypeAdapter<T> extends SerializationDelegatingTypeAdapter<T> {
private final JsonSerializer<T> serializer;
private final JsonDeserializer<T> deserializer;
final Gson gson;
private final TypeToken<T> typeToken;
private final TypeAdapterFactory skipPast;
private final GsonContextImpl context = new GsonContextImpl();
private final boolean nullSafe;
/** The delegate is lazily created because it may not be needed, and creating it may fail. */
private volatile TypeAdapter<T> delegate;
public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deserializer,
Gson gson, TypeToken<T> typeToken, TypeAdapterFactory skipPast, boolean nullSafe) {
this.serializer = serializer;
this.deserializer = deserializer;
this.gson = gson;
this.typeToken = typeToken;
this.skipPast = skipPast;
this.nullSafe = nullSafe;
}
public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deserializer,
Gson gson, TypeToken<T> typeToken, TypeAdapterFactory skipPast) {
this(serializer, deserializer, gson, typeToken, skipPast, true);
}
@Override public T read(JsonReader in) throws IOException {
if (deserializer == null) {
return delegate().read(in);
}
JsonElement value = Streams.parse(in);
if (nullSafe && value.isJsonNull()) {
return null;
}
return deserializer.deserialize(value, typeToken.getType(), context);
}
@Override public void write(JsonWriter out, T value) throws IOException {
if (serializer == null) {
delegate().write(out, value);
return;
}
if (nullSafe && value == null) {
out.nullValue();
return;
}
JsonElement tree = serializer.serialize(value, typeToken.getType(), context);
Streams.write(tree, out);
}
private TypeAdapter<T> delegate() {
// A race might lead to `delegate` being assigned by multiple threads but the last assignment will stick
TypeAdapter<T> d = delegate;
return d != null
? d
: (delegate = gson.getDelegateAdapter(skipPast, typeToken));
}
/**
* Returns the type adapter which is used for serialization. Returns {@code this}
* if this {@code TreeTypeAdapter} has a {@link #serializer}; otherwise returns
* the delegate.
*/
@Override public TypeAdapter<T> getSerializationDelegate() {
return serializer != null ? this : delegate();
}
/**
* Returns a new factory that will match each type against {@code exactType}.
*/
public static TypeAdapterFactory newFactory(TypeToken<?> exactType, Object typeAdapter) {
return new SingleTypeFactory(typeAdapter, exactType, false, null);
}
/**
* Returns a new factory that will match each type and its raw type against
* {@code exactType}.
*/
public static TypeAdapterFactory newFactoryWithMatchRawType(
TypeToken<?> exactType, Object typeAdapter) {
// only bother matching raw types if exact type is a raw type
boolean matchRawType = exactType.getType() == exactType.getRawType();
return new SingleTypeFactory(typeAdapter, exactType, matchRawType, null);
}
/**
* Returns a new factory that will match each type's raw type for assignability
* to {@code hierarchyType}.
*/
public static TypeAdapterFactory newTypeHierarchyFactory(
Class<?> hierarchyType, Object typeAdapter) {
return new SingleTypeFactory(typeAdapter, null, false, hierarchyType);
}
private static final class SingleTypeFactory implements TypeAdapterFactory {
private final TypeToken<?> exactType;
private final boolean matchRawType;
private final Class<?> hierarchyType;
private final JsonSerializer<?> serializer;
private final JsonDeserializer<?> deserializer;
SingleTypeFactory(Object typeAdapter, TypeToken<?> exactType, boolean matchRawType,
Class<?> hierarchyType) {
serializer = typeAdapter instanceof JsonSerializer
? (JsonSerializer<?>) typeAdapter
: null;
deserializer = typeAdapter instanceof JsonDeserializer
? (JsonDeserializer<?>) typeAdapter
: null;
$Gson$Preconditions.checkArgument(serializer != null || deserializer != null);
this.exactType = exactType;
this.matchRawType = matchRawType;
this.hierarchyType = hierarchyType;
}
@SuppressWarnings("unchecked") // guarded by typeToken.equals() call
@Override
public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
boolean matches = exactType != null
? exactType.equals(type) || matchRawType && exactType.getType() == type.getRawType()
: hierarchyType.isAssignableFrom(type.getRawType());
return matches
? new TreeTypeAdapter<>((JsonSerializer<T>) serializer,
(JsonDeserializer<T>) deserializer, gson, type, this)
: null;
}
}
private final class GsonContextImpl implements JsonSerializationContext, JsonDeserializationContext {
@Override public JsonElement serialize(Object src) {
return gson.toJsonTree(src);
}
@Override public JsonElement serialize(Object src, Type typeOfSrc) {
return gson.toJsonTree(src, typeOfSrc);
}
@SuppressWarnings("unchecked")
@Override public <R> R deserialize(JsonElement json, Type typeOfT) throws JsonParseException {
return gson.fromJson(json, typeOfT);
}
}
}
|
