gson-comments/gson/src/main/java/com/google/gson/internal/bind/ReflectiveTypeAdapterFactor...

300 lines
11 KiB
Java

/*
* 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.FieldNamingStrategy;
import com.google.gson.Gson;
import com.google.gson.JsonIOException;
import com.google.gson.JsonSyntaxException;
import com.google.gson.ReflectionAccessFilter;
import com.google.gson.ReflectionAccessFilter.FilterResult;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.annotations.JsonAdapter;
import com.google.gson.annotations.SerializedName;
import com.google.gson.internal.$Gson$Types;
import com.google.gson.internal.ConstructorConstructor;
import com.google.gson.internal.Excluder;
import com.google.gson.internal.ObjectConstructor;
import com.google.gson.internal.Primitives;
import com.google.gson.internal.ReflectionAccessFilterHelper;
import com.google.gson.internal.reflect.ReflectionHelper;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* Type adapter that reflects over the fields and methods of a class.
*/
public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
private final ConstructorConstructor constructorConstructor;
private final FieldNamingStrategy fieldNamingPolicy;
private final Excluder excluder;
private final JsonAdapterAnnotationTypeAdapterFactory jsonAdapterFactory;
private final List<ReflectionAccessFilter> reflectionFilters;
public ReflectiveTypeAdapterFactory(ConstructorConstructor constructorConstructor,
FieldNamingStrategy fieldNamingPolicy, Excluder excluder,
JsonAdapterAnnotationTypeAdapterFactory jsonAdapterFactory,
List<ReflectionAccessFilter> reflectionFilters) {
this.constructorConstructor = constructorConstructor;
this.fieldNamingPolicy = fieldNamingPolicy;
this.excluder = excluder;
this.jsonAdapterFactory = jsonAdapterFactory;
this.reflectionFilters = reflectionFilters;
}
public boolean excludeField(Field f, boolean serialize) {
return excludeField(f, serialize, excluder);
}
static boolean excludeField(Field f, boolean serialize, Excluder excluder) {
return !excluder.excludeClass(f.getType(), serialize) && !excluder.excludeField(f, serialize);
}
/** first element holds the default name */
private List<String> getFieldNames(Field f) {
SerializedName annotation = f.getAnnotation(SerializedName.class);
if (annotation == null) {
String name = fieldNamingPolicy.translateName(f);
return Collections.singletonList(name);
}
String serializedName = annotation.value();
String[] alternates = annotation.alternate();
if (alternates.length == 0) {
return Collections.singletonList(serializedName);
}
List<String> fieldNames = new ArrayList<>(alternates.length + 1);
fieldNames.add(serializedName);
for (String alternate : alternates) {
fieldNames.add(alternate);
}
return fieldNames;
}
@Override public <T> TypeAdapter<T> create(Gson gson, final TypeToken<T> type) {
Class<? super T> raw = type.getRawType();
if (!Object.class.isAssignableFrom(raw)) {
return null; // it's a primitive!
}
FilterResult filterResult = ReflectionAccessFilterHelper.getFilterResult(reflectionFilters, raw);
if (filterResult == FilterResult.BLOCK_ALL) {
throw new JsonIOException("ReflectionAccessFilter does not permit using reflection for "
+ raw + ". Register a TypeAdapter for this type or adjust the access filter.");
}
boolean blockInaccessible = filterResult == FilterResult.BLOCK_INACCESSIBLE;
ObjectConstructor<T> constructor = constructorConstructor.get(type);
return new Adapter<>(constructor, getBoundFields(gson, type, raw, blockInaccessible));
}
private static void checkAccessible(Object object, Field field) {
if (!ReflectionAccessFilterHelper.canAccess(field, Modifier.isStatic(field.getModifiers()) ? null : object)) {
throw new JsonIOException("Field '" + field.getDeclaringClass().getName() + "#"
+ field.getName() + "' is not accessible and ReflectionAccessFilter does not "
+ "permit making it accessible. Register a TypeAdapter for the declaring type "
+ "or adjust the access filter.");
}
}
private ReflectiveTypeAdapterFactory.BoundField createBoundField(
final Gson context, final Field field, final String name,
final TypeToken<?> fieldType, boolean serialize, boolean deserialize,
final boolean blockInaccessible) {
final boolean isPrimitive = Primitives.isPrimitive(fieldType.getRawType());
// special casing primitives here saves ~5% on Android...
JsonAdapter annotation = field.getAnnotation(JsonAdapter.class);
TypeAdapter<?> mapped = null;
if (annotation != null) {
mapped = jsonAdapterFactory.getTypeAdapter(
constructorConstructor, context, fieldType, annotation);
}
final boolean jsonAdapterPresent = mapped != null;
if (mapped == null) mapped = context.getAdapter(fieldType);
final TypeAdapter<?> typeAdapter = mapped;
return new ReflectiveTypeAdapterFactory.BoundField(name, serialize, deserialize) {
@SuppressWarnings({"unchecked", "rawtypes"}) // the type adapter and field type always agree
@Override void write(JsonWriter writer, Object value)
throws IOException, IllegalAccessException {
if (!serialized) return;
if (blockInaccessible) {
checkAccessible(value, field);
}
Object fieldValue = field.get(value);
if (fieldValue == value) {
// avoid direct recursion
return;
}
writer.name(name);
TypeAdapter t = jsonAdapterPresent ? typeAdapter
: new TypeAdapterRuntimeTypeWrapper(context, typeAdapter, fieldType.getType());
t.write(writer, fieldValue);
}
@Override void read(JsonReader reader, Object value)
throws IOException, IllegalAccessException {
Object fieldValue = typeAdapter.read(reader);
if (fieldValue != null || !isPrimitive) {
if (blockInaccessible) {
checkAccessible(value, field);
}
field.set(value, fieldValue);
}
}
};
}
private Map<String, BoundField> getBoundFields(Gson context, TypeToken<?> type, Class<?> raw, boolean blockInaccessible) {
Map<String, BoundField> result = new LinkedHashMap<>();
if (raw.isInterface()) {
return result;
}
Type declaredType = type.getType();
Class<?> originalRaw = raw;
while (raw != Object.class) {
Field[] fields = raw.getDeclaredFields();
// For inherited fields, check if access to their declaring class is allowed
if (raw != originalRaw && fields.length > 0) {
FilterResult filterResult = ReflectionAccessFilterHelper.getFilterResult(reflectionFilters, raw);
if (filterResult == FilterResult.BLOCK_ALL) {
throw new JsonIOException("ReflectionAccessFilter does not permit using reflection for "
+ raw + " (supertype of " + originalRaw + "). Register a TypeAdapter for this type "
+ "or adjust the access filter.");
}
blockInaccessible = filterResult == FilterResult.BLOCK_INACCESSIBLE;
}
for (Field field : fields) {
boolean serialize = excludeField(field, true);
boolean deserialize = excludeField(field, false);
if (!serialize && !deserialize) {
continue;
}
// If blockInaccessible, skip and perform access check later
if (!blockInaccessible) {
ReflectionHelper.makeAccessible(field);
}
Type fieldType = $Gson$Types.resolve(type.getType(), raw, field.getGenericType());
List<String> fieldNames = getFieldNames(field);
BoundField previous = null;
for (int i = 0, size = fieldNames.size(); i < size; ++i) {
String name = fieldNames.get(i);
if (i != 0) serialize = false; // only serialize the default name
BoundField boundField = createBoundField(context, field, name,
TypeToken.get(fieldType), serialize, deserialize, blockInaccessible);
BoundField replaced = result.put(name, boundField);
if (previous == null) previous = replaced;
}
if (previous != null) {
throw new IllegalArgumentException(declaredType
+ " declares multiple JSON fields named " + previous.name);
}
}
type = TypeToken.get($Gson$Types.resolve(type.getType(), raw, raw.getGenericSuperclass()));
raw = type.getRawType();
}
return result;
}
static abstract class BoundField {
final String name;
final boolean serialized;
final boolean deserialized;
protected BoundField(String name, boolean serialized, boolean deserialized) {
this.name = name;
this.serialized = serialized;
this.deserialized = deserialized;
}
abstract void write(JsonWriter writer, Object value) throws IOException, IllegalAccessException;
abstract void read(JsonReader reader, Object value) throws IOException, IllegalAccessException;
}
public static final class Adapter<T> extends TypeAdapter<T> {
private final ObjectConstructor<T> constructor;
private final Map<String, BoundField> boundFields;
Adapter(ObjectConstructor<T> constructor, Map<String, BoundField> boundFields) {
this.constructor = constructor;
this.boundFields = boundFields;
}
@Override public T read(JsonReader in) throws IOException {
if (in.peek() == JsonToken.NULL) {
in.nextNull();
return null;
}
T instance = constructor.construct();
try {
in.beginObject();
while (in.hasNext()) {
String name = in.nextName();
BoundField field = boundFields.get(name);
if (field == null || !field.deserialized) {
in.skipValue();
} else {
field.read(in, instance);
}
}
} catch (IllegalStateException e) {
throw new JsonSyntaxException(e);
} catch (IllegalAccessException e) {
throw ReflectionHelper.createExceptionForUnexpectedIllegalAccess(e);
}
in.endObject();
return instance;
}
@Override public void write(JsonWriter out, T value) throws IOException {
if (value == null) {
out.nullValue();
return;
}
out.beginObject();
try {
for (BoundField boundField : boundFields.values()) {
boundField.write(out, value);
}
} catch (IllegalAccessException e) {
throw ReflectionHelper.createExceptionForUnexpectedIllegalAccess(e);
}
out.endObject();
}
}
}