/*
* 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.internal;
import com.google.gson.ExclusionStrategy;
import com.google.gson.FieldAttributes;
import com.google.gson.Gson;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.Since;
import com.google.gson.annotations.Until;
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.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* This class selects which fields and types to omit. It is configurable,
* supporting version attributes {@link Since} and {@link Until}, modifiers,
* synthetic fields, anonymous and local classes, inner classes, and fields with
* the {@link Expose} annotation.
*
* <p>This class is a type adapter factory; types that are excluded will be
* adapted to null. It may delegate to another type adapter if only one
* direction is excluded.
*
* @author Joel Leitch
* @author Jesse Wilson
*/
public final class Excluder implements TypeAdapterFactory, Cloneable {
private static final double IGNORE_VERSIONS = -1.0d;
public static final Excluder DEFAULT = new Excluder();
private double version = IGNORE_VERSIONS;
private int modifiers = Modifier.TRANSIENT | Modifier.STATIC;
private boolean serializeInnerClasses = true;
private boolean requireExpose;
private List<ExclusionStrategy> serializationStrategies = Collections.emptyList();
private List<ExclusionStrategy> deserializationStrategies = Collections.emptyList();
@Override protected Excluder clone() {
try {
return (Excluder) super.clone();
} catch (CloneNotSupportedException e) {
throw new AssertionError();
}
}
public Excluder withVersion(double ignoreVersionsAfter) {
Excluder result = clone();
result.version = ignoreVersionsAfter;
return result;
}
public Excluder withModifiers(int... modifiers) {
Excluder result = clone();
result.modifiers = 0;
for (int modifier : modifiers) {
result.modifiers |= modifier;
}
return result;
}
public Excluder disableInnerClassSerialization() {
Excluder result = clone();
result.serializeInnerClasses = false;
return result;
}
public Excluder excludeFieldsWithoutExposeAnnotation() {
Excluder result = clone();
result.requireExpose = true;
return result;
}
public Excluder withExclusionStrategy(ExclusionStrategy exclusionStrategy,
boolean serialization, boolean deserialization) {
Excluder result = clone();
if (serialization) {
result.serializationStrategies = new ArrayList<ExclusionStrategy>(serializationStrategies);
result.serializationStrategies.add(exclusionStrategy);
}
if (deserialization) {
result.deserializationStrategies
= new ArrayList<ExclusionStrategy>(deserializationStrategies);
result.deserializationStrategies.add(exclusionStrategy);
}
return result;
}
public <T> TypeAdapter<T> create(final Gson gson, final TypeToken<T> type) {
Class<?> rawType = type.getRawType();
final boolean skipSerialize = excludeClass(rawType, true);
final boolean skipDeserialize = excludeClass(rawType, false);
if (!skipSerialize && !skipDeserialize) {
return null;
}
return new TypeAdapter<T>() {
/** The delegate is lazily created because it may not be needed, and creating it may fail. */
private TypeAdapter<T> delegate;
@Override public T read(JsonReader in) throws IOException {
if (skipDeserialize) {
in.skipValue();
return null;
}
return delegate().read(in);
}
@Override public void write(JsonWriter out, T value) throws IOException {
if (skipSerialize) {
out.nullValue();
return;
}
delegate().write(out, value);
}
private TypeAdapter<T> delegate() {
TypeAdapter<T> d = delegate;
return d != null
? d
: (delegate = GsonInternalAccess.INSTANCE.getNextAdapter(gson, Excluder.this, type));
}
};
}
public boolean excludeField(Field field, boolean serialize) {
if ((modifiers & field.getModifiers()) != 0) {
return true;
}
if (version != Excluder.IGNORE_VERSIONS
&& !isValidVersion(field.getAnnotation(Since.class), field.getAnnotation(Until.class))) {
return true;
}
if (field.isSynthetic()) {
return true;
}
if (requireExpose) {
Expose annotation = field.getAnnotation(Expose.class);
if (annotation == null || (serialize ? !annotation.serialize() : !annotation.deserialize())) {
return true;
}
}
if (!serializeInnerClasses && isInnerClass(field.getType())) {
return true;
}
if (isAnonymousOrLocal(field.getType())) {
return true;
}
List<ExclusionStrategy> list = serialize ? serializationStrategies : deserializationStrategies;
if (!list.isEmpty()) {
FieldAttributes fieldAttributes = new FieldAttributes(field);
for (ExclusionStrategy exclusionStrategy : list) {
if (exclusionStrategy.shouldSkipField(fieldAttributes)) {
return true;
}
}
}
return false;
}
public boolean excludeClass(Class<?> clazz, boolean serialize) {
if (version != Excluder.IGNORE_VERSIONS
&& !isValidVersion(clazz.getAnnotation(Since.class), clazz.getAnnotation(Until.class))) {
return true;
}
if (!serializeInnerClasses && isInnerClass(clazz)) {
return true;
}
if (isAnonymousOrLocal(clazz)) {
return true;
}
List<ExclusionStrategy> list = serialize ? serializationStrategies : deserializationStrategies;
for (ExclusionStrategy exclusionStrategy : list) {
if (exclusionStrategy.shouldSkipClass(clazz)) {
return true;
}
}
return false;
}
private boolean isAnonymousOrLocal(Class<?> clazz) {
return !Enum.class.isAssignableFrom(clazz)
&& (clazz.isAnonymousClass() || clazz.isLocalClass());
}
private boolean isInnerClass(Class<?> clazz) {
return clazz.isMemberClass() && !isStatic(clazz);
}
private boolean isStatic(Class<?> clazz) {
return (clazz.getModifiers() & Modifier.STATIC) != 0;
}
private boolean isValidVersion(Since since, Until until) {
return isValidSince(since) && isValidUntil(until);
}
private boolean isValidSince(Since annotation) {
if (annotation != null) {
double annotationVersion = annotation.value();
if (annotationVersion > version) {
return false;
}
}
return true;
}
private boolean isValidUntil(Until annotation) {
if (annotation != null) {
double annotationVersion = annotation.value();
if (annotationVersion <= version) {
return false;
}
}
return true;
}
}