/*
* Copyright (C) 2009 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.smartandroid.sa.json;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import com.smartandroid.sa.json.internal.$Gson$Preconditions;
import com.smartandroid.sa.json.internal.$Gson$Types;
/**
* A data object that stores attributes of a field.
*
* <p>
* This class is immutable; therefore, it can be safely shared across threads.
*
* @author Inderjeet Singh
* @author Joel Leitch
*
* @since 1.4
*/
public final class FieldAttributes {
private static final String MAX_CACHE_PROPERTY_NAME = "com.google.gson.annotation_cache_size_hint";
private static final Cache<Pair<Class<?>, String>, Collection<Annotation>> ANNOTATION_CACHE = new LruCache<Pair<Class<?>, String>, Collection<Annotation>>(
getMaxCacheSize());
private final Class<?> declaringClazz;
private final Field field;
private final Class<?> declaredType;
private final boolean isSynthetic;
private final int modifiers;
private final String name;
private final Type resolvedType;
// Fields used for lazy initialization
private Type genericType;
private Collection<Annotation> annotations;
/**
* Constructs a Field Attributes object from the {@code f}.
*
* @param f
* the field to pull attributes from
* @param declaringType
* The type in which the field is declared
*/
FieldAttributes(Class<?> declaringClazz, Field f, Type declaringType) {
this.declaringClazz = $Gson$Preconditions.checkNotNull(declaringClazz);
this.name = f.getName();
this.declaredType = f.getType();
this.isSynthetic = f.isSynthetic();
this.modifiers = f.getModifiers();
this.field = f;
this.resolvedType = getTypeInfoForField(f, declaringType);
}
private static int getMaxCacheSize() {
final int defaultMaxCacheSize = 2000;
try {
String propertyValue = System.getProperty(MAX_CACHE_PROPERTY_NAME,
String.valueOf(defaultMaxCacheSize));
return Integer.parseInt(propertyValue);
} catch (NumberFormatException e) {
return defaultMaxCacheSize;
}
}
/**
* @return the declaring class that contains this field
*/
public Class<?> getDeclaringClass() {
return declaringClazz;
}
/**
* @return the name of the field
*/
public String getName() {
return name;
}
/**
* <p>
* For example, assume the following class definition:
*
* <pre class="code">
* public class Foo {
* private String bar;
* private List<String> red;
* }
*
* Type listParmeterizedType = new TypeToken<List<String>>() {
* }.getType();
* </pre>
*
* <p>
* This method would return {@code String.class} for the {@code bar} field
* and {@code listParameterizedType} for the {@code red} field.
*
* @return the specific type declared for this field
*/
public Type getDeclaredType() {
if (genericType == null) {
genericType = field.getGenericType();
}
return genericType;
}
/**
* Returns the {@code Class<?>} object that was declared for this field.
*
* <p>
* For example, assume the following class definition:
*
* <pre class="code">
* public class Foo {
* private String bar;
* private List<String> red;
* }
* </pre>
*
* <p>
* This method would return {@code String.class} for the {@code bar} field
* and {@code List.class} for the {@code red} field.
*
* @return the specific class object that was declared for the field
*/
public Class<?> getDeclaredClass() {
return declaredType;
}
/**
* Return the {@code T} annotation object from this field if it exist;
* otherwise returns {@code null}.
*
* @param annotation
* the class of the annotation that will be retrieved
* @return the annotation instance if it is bound to the field; otherwise
* {@code null}
*/
public <T extends Annotation> T getAnnotation(Class<T> annotation) {
return getAnnotationFromArray(getAnnotations(), annotation);
}
/**
* Return the annotations that are present on this field.
*
* @return an array of all the annotations set on the field
* @since 1.4
*/
public Collection<Annotation> getAnnotations() {
if (annotations == null) {
Pair<Class<?>, String> key = new Pair<Class<?>, String>(
declaringClazz, name);
Collection<Annotation> cachedValue = ANNOTATION_CACHE
.getElement(key);
if (cachedValue == null) {
cachedValue = Collections.unmodifiableCollection(Arrays
.asList(field.getAnnotations()));
ANNOTATION_CACHE.addElement(key, cachedValue);
}
annotations = cachedValue;
}
return annotations;
}
/**
* Returns {@code true} if the field is defined with the {@code modifier}.
*
* <p>
* This method is meant to be called as:
*
* <pre class="code">
* boolean hasPublicModifier = fieldAttribute
* .hasModifier(java.lang.reflect.Modifier.PUBLIC);
* </pre>
*
* @see java.lang.reflect.Modifier
*/
public boolean hasModifier(int modifier) {
return (modifiers & modifier) != 0;
}
/**
* This is exposed internally only for the removing synthetic fields from
* the JSON output.
*
* @throws IllegalAccessException
* @throws IllegalArgumentException
*/
void set(Object instance, Object value) throws IllegalAccessException {
field.set(instance, value);
}
/**
* This is exposed internally only for the removing synthetic fields from
* the JSON output.
*
* @return true if the field is synthetic; otherwise false
* @throws IllegalAccessException
* @throws IllegalArgumentException
*/
Object get(Object instance) throws IllegalAccessException {
return field.get(instance);
}
/**
* This is exposed internally only for the removing synthetic fields from
* the JSON output.
*
* @return true if the field is synthetic; otherwise false
*/
boolean isSynthetic() {
return isSynthetic;
}
/**
* @deprecated remove this when {@link FieldNamingStrategy} is deleted.
*/
@Deprecated
Field getFieldObject() {
return field;
}
Type getResolvedType() {
return resolvedType;
}
@SuppressWarnings("unchecked")
private static <T extends Annotation> T getAnnotationFromArray(
Collection<Annotation> annotations, Class<T> annotation) {
for (Annotation a : annotations) {
if (a.annotationType() == annotation) {
return (T) a;
}
}
return null;
}
/**
* Evaluates the "actual" type for the field. If the field is a
* "TypeVariable" or has a "TypeVariable" in a parameterized type then it
* evaluates the real type.
*
* @param f
* the actual field object to retrieve the type from
* @param typeDefiningF
* the type that contains the field {@code f}
* @return the type information for the field
*/
static Type getTypeInfoForField(Field f, Type typeDefiningF) {
Class<?> rawType = $Gson$Types.getRawType(typeDefiningF);
if (!f.getDeclaringClass().isAssignableFrom(rawType)) {
// this field is unrelated to the type; the user probably omitted
// type information
return f.getGenericType();
}
return $Gson$Types.resolve(typeDefiningF, rawType, f.getGenericType());
}
}