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1 | /* | |
2 | * Copyright (C) 2008 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; | |
18 | ||
19 | import com.google.gson.ExclusionStrategy; | |
20 | import com.google.gson.FieldAttributes; | |
21 | import com.google.gson.Gson; | |
22 | import com.google.gson.TypeAdapter; | |
23 | import com.google.gson.TypeAdapterFactory; | |
24 | import com.google.gson.annotations.Expose; | |
25 | import com.google.gson.annotations.Since; | |
26 | import com.google.gson.annotations.Until; | |
27 | import com.google.gson.reflect.TypeToken; | |
28 | import com.google.gson.stream.JsonReader; | |
29 | import com.google.gson.stream.JsonWriter; | |
30 | import java.io.IOException; | |
31 | import java.lang.reflect.Field; | |
32 | import java.lang.reflect.Modifier; | |
33 | import java.util.ArrayList; | |
34 | import java.util.Collections; | |
35 | import java.util.List; | |
36 | ||
37 | /** | |
38 | * This class selects which fields and types to omit. It is configurable, | |
39 | * supporting version attributes {@link Since} and {@link Until}, modifiers, | |
40 | * synthetic fields, anonymous and local classes, inner classes, and fields with | |
41 | * the {@link Expose} annotation. | |
42 | * | |
43 | * <p>This class is a type adapter factory; types that are excluded will be | |
44 | * adapted to null. It may delegate to another type adapter if only one | |
45 | * direction is excluded. | |
46 | * | |
47 | * @author Joel Leitch | |
48 | * @author Jesse Wilson | |
49 | */ | |
50 | public final class Excluder implements TypeAdapterFactory, Cloneable { | |
51 | private static final double IGNORE_VERSIONS = -1.0d; | |
52 | public static final Excluder DEFAULT = new Excluder(); | |
53 | ||
54 | private double version = IGNORE_VERSIONS; | |
55 | private int modifiers = Modifier.TRANSIENT | Modifier.STATIC; | |
56 | private boolean serializeInnerClasses = true; | |
57 | private boolean requireExpose; | |
58 | private List<ExclusionStrategy> serializationStrategies = Collections.emptyList(); | |
59 | private List<ExclusionStrategy> deserializationStrategies = Collections.emptyList(); | |
60 | ||
61 | @Override protected Excluder clone() { | |
62 | try { | |
63 | return (Excluder) super.clone(); | |
64 | } catch (CloneNotSupportedException e) { | |
65 | throw new AssertionError(); | |
66 | } | |
67 | } | |
68 | ||
69 | public Excluder withVersion(double ignoreVersionsAfter) { | |
70 | Excluder result = clone(); | |
71 | result.version = ignoreVersionsAfter; | |
72 | return result; | |
73 | } | |
74 | ||
75 | public Excluder withModifiers(int... modifiers) { | |
76 | Excluder result = clone(); | |
77 | result.modifiers = 0; | |
78 | for (int modifier : modifiers) { | |
79 | result.modifiers |= modifier; | |
80 | } | |
81 | return result; | |
82 | } | |
83 | ||
84 | public Excluder disableInnerClassSerialization() { | |
85 | Excluder result = clone(); | |
86 | result.serializeInnerClasses = false; | |
87 | return result; | |
88 | } | |
89 | ||
90 | public Excluder excludeFieldsWithoutExposeAnnotation() { | |
91 | Excluder result = clone(); | |
92 | result.requireExpose = true; | |
93 | return result; | |
94 | } | |
95 | ||
96 | public Excluder withExclusionStrategy(ExclusionStrategy exclusionStrategy, | |
97 | boolean serialization, boolean deserialization) { | |
98 | Excluder result = clone(); | |
99 | if (serialization) { | |
100 | result.serializationStrategies = new ArrayList<ExclusionStrategy>(serializationStrategies); | |
101 | result.serializationStrategies.add(exclusionStrategy); | |
102 | } | |
103 | if (deserialization) { | |
104 | result.deserializationStrategies | |
105 | = new ArrayList<ExclusionStrategy>(deserializationStrategies); | |
106 | result.deserializationStrategies.add(exclusionStrategy); | |
107 | } | |
108 | return result; | |
109 | } | |
110 | ||
111 | public <T> TypeAdapter<T> create(final Gson gson, final TypeToken<T> type) { | |
112 | Class<?> rawType = type.getRawType(); | |
113 | final boolean skipSerialize = excludeClass(rawType, true); | |
114 | final boolean skipDeserialize = excludeClass(rawType, false); | |
115 | ||
116 | if (!skipSerialize && !skipDeserialize) { | |
117 | return null; | |
118 | } | |
119 | ||
120 | return new TypeAdapter<T>() { | |
121 | /** The delegate is lazily created because it may not be needed, and creating it may fail. */ | |
122 | private TypeAdapter<T> delegate; | |
123 | ||
124 | @Override public T read(JsonReader in) throws IOException { | |
125 | if (skipDeserialize) { | |
126 | in.skipValue(); | |
127 | return null; | |
128 | } | |
129 | return delegate().read(in); | |
130 | } | |
131 | ||
132 | @Override public void write(JsonWriter out, T value) throws IOException { | |
133 | if (skipSerialize) { | |
134 | out.nullValue(); | |
135 | return; | |
136 | } | |
137 | delegate().write(out, value); | |
138 | } | |
139 | ||
140 | private TypeAdapter<T> delegate() { | |
141 | TypeAdapter<T> d = delegate; | |
142 | return d != null | |
143 | ? d | |
144 | : (delegate = gson.getDelegateAdapter(Excluder.this, type)); | |
145 | } | |
146 | }; | |
147 | } | |
148 | ||
149 | public boolean excludeField(Field field, boolean serialize) { | |
150 | if ((modifiers & field.getModifiers()) != 0) { | |
151 | return true; | |
152 | } | |
153 | ||
154 | if (version != Excluder.IGNORE_VERSIONS | |
155 | && !isValidVersion(field.getAnnotation(Since.class), field.getAnnotation(Until.class))) { | |
156 | return true; | |
157 | } | |
158 | ||
159 | if (field.isSynthetic()) { | |
160 | return true; | |
161 | } | |
162 | ||
163 | if (requireExpose) { | |
164 | Expose annotation = field.getAnnotation(Expose.class); | |
165 | if (annotation == null || (serialize ? !annotation.serialize() : !annotation.deserialize())) { | |
166 | return true; | |
167 | } | |
168 | } | |
169 | ||
170 | if (!serializeInnerClasses && isInnerClass(field.getType())) { | |
171 | return true; | |
172 | } | |
173 | ||
174 | if (isAnonymousOrLocal(field.getType())) { | |
175 | return true; | |
176 | } | |
177 | ||
178 | List<ExclusionStrategy> list = serialize ? serializationStrategies : deserializationStrategies; | |
179 | if (!list.isEmpty()) { | |
180 | FieldAttributes fieldAttributes = new FieldAttributes(field); | |
181 | for (ExclusionStrategy exclusionStrategy : list) { | |
182 | if (exclusionStrategy.shouldSkipField(fieldAttributes)) { | |
183 | return true; | |
184 | } | |
185 | } | |
186 | } | |
187 | ||
188 | return false; | |
189 | } | |
190 | ||
191 | public boolean excludeClass(Class<?> clazz, boolean serialize) { | |
192 | if (version != Excluder.IGNORE_VERSIONS | |
193 | && !isValidVersion(clazz.getAnnotation(Since.class), clazz.getAnnotation(Until.class))) { | |
194 | return true; | |
195 | } | |
196 | ||
197 | if (!serializeInnerClasses && isInnerClass(clazz)) { | |
198 | return true; | |
199 | } | |
200 | ||
201 | if (isAnonymousOrLocal(clazz)) { | |
202 | return true; | |
203 | } | |
204 | ||
205 | List<ExclusionStrategy> list = serialize ? serializationStrategies : deserializationStrategies; | |
206 | for (ExclusionStrategy exclusionStrategy : list) { | |
207 | if (exclusionStrategy.shouldSkipClass(clazz)) { | |
208 | return true; | |
209 | } | |
210 | } | |
211 | ||
212 | return false; | |
213 | } | |
214 | ||
215 | private boolean isAnonymousOrLocal(Class<?> clazz) { | |
216 | return !Enum.class.isAssignableFrom(clazz) | |
217 | && (clazz.isAnonymousClass() || clazz.isLocalClass()); | |
218 | } | |
219 | ||
220 | private boolean isInnerClass(Class<?> clazz) { | |
221 | return clazz.isMemberClass() && !isStatic(clazz); | |
222 | } | |
223 | ||
224 | private boolean isStatic(Class<?> clazz) { | |
225 | return (clazz.getModifiers() & Modifier.STATIC) != 0; | |
226 | } | |
227 | ||
228 | private boolean isValidVersion(Since since, Until until) { | |
229 | return isValidSince(since) && isValidUntil(until); | |
230 | } | |
231 | ||
232 | private boolean isValidSince(Since annotation) { | |
233 | if (annotation != null) { | |
234 | double annotationVersion = annotation.value(); | |
235 | if (annotationVersion > version) { | |
236 | return false; | |
237 | } | |
238 | } | |
239 | return true; | |
240 | } | |
241 | ||
242 | private boolean isValidUntil(Until annotation) { | |
243 | if (annotation != null) { | |
244 | double annotationVersion = annotation.value(); | |
245 | if (annotationVersion <= version) { | |
246 | return false; | |
247 | } | |
248 | } | |
249 | return true; | |
250 | } | |
251 | } |