/*
* Copyright 2013 MovingBlocks
*
* 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 org.terasology.reflection.metadata;
import com.google.common.base.Objects;
import com.google.gson.annotations.SerializedName;
import org.terasology.reflection.copy.CopyStrategy;
import org.terasology.reflection.reflect.FieldAccessor;
import org.terasology.reflection.reflect.InaccessibleFieldException;
import org.terasology.reflection.reflect.ReflectFactory;
import org.terasology.utilities.ReflectionUtil;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
/**
* Provides information on a field, and the ability to set and get that field.
*
* @param <T> The type of the object this field belongs to
* @param <U> The type of the field itself
*/
public class FieldMetadata<T, U> {
private final ClassMetadata<T, ?> owner;
private final Class<U> type;
private final Field field;
private final FieldAccessor<T, U> accessor;
private final CopyStrategy<U> copyStrategy;
private final String serializationName;
private byte id;
/**
* @param owner The ClassMetadata that owns this field
* @param field The field this metadata is for
* @param copyStrategy The CopyStrategy appropriate for the type of the field
* @param factory The reflection provider
*/
@SuppressWarnings("unchecked")
public FieldMetadata(ClassMetadata<T, ?> owner, Field field, CopyStrategy<U> copyStrategy, ReflectFactory factory) throws InaccessibleFieldException {
this.owner = owner;
this.copyStrategy = copyStrategy;
this.type = (Class<U>) determineType(field, owner.getType());
this.accessor = factory.createFieldAccessor(owner.getType(), field, type);
this.field = field;
SerializedName name = field.getAnnotation(SerializedName.class);
if (name != null) {
serializationName = name.value();
} else {
serializationName = field.getName();
}
}
private static Class<?> determineType(Field field, Class<?> ownerType) {
Method getter = ReflectionUtil.findGetter(field.getName(), ownerType);
if (getter != null && getter.getReturnType() != null) {
if (ReflectionUtil.findSetter(field.getName(), ownerType, getter.getReturnType()) != null) {
return getter.getReturnType();
}
}
return field.getType();
}
/**
* @return The class that owns this field
*/
public ClassMetadata<T, ?> getOwner() {
return owner;
}
/**
* @return The name of the field
*/
public String getName() {
return field.getName();
}
/**
* @return The serialization name of the field
*/
public String getSerializationName() {
return serializationName;
}
/**
* @return The underlying java field
*/
public Field getField() {
return field;
}
/**
* @return The type of the field
*/
public Class<U> getType() {
return type;
}
/**
* @return The assigned id for this field, if any
*/
public byte getId() {
return id;
}
/**
* @param id The id to assign for this field
*/
public void setId(byte id) {
this.id = id;
owner.setFieldId(this, id);
}
/**
* Obtains the value of the field from a object which is an instance of the owning type.
*
* @param from The object to obtain the value of this field from
* @return The value of the field
*/
@SuppressWarnings("unchecked")
public U getValue(Object from) {
return accessor.getValue((T) from);
}
/**
* Obtains the value of the field from a object which is an instance of the owning type.
* This method is checked to conform to the generic parameters of the FieldMetadata
*
* @param from The object to obtain the value of this field from
* @return The value of the field
*/
public U getValueChecked(T from) {
return getValue(from);
}
/**
* For types that need to be copied (e.g. Vector3f) for safe usage, this method will create a new copy of a field from an object.
* Otherwise it behaves the same as getValue
*
* @param from The object to copy the field from
* @return A safe to use copy of the value of this field in the given object
*/
public U getCopyOfValue(Object from) {
return copyStrategy.copy(getValue(from));
}
/**
* For types that need to be copied (e.g. Vector3f) for safe usage, this method will create a new copy of a field from an object.
* Otherwise it behaves the same as getValue
* This method is checked to conform to the generic parameters of the FieldMetadata
*
* @param from The object to copy the field from
* @return A safe to use copy of the value of this field in the given object
*/
public U getCopyOfValueChecked(T from) {
return getCopyOfValue(from);
}
/**
* Sets the value of this field in a target object
*
* @param target The object to set the field of
* @param value The value to set the field to
*/
@SuppressWarnings("unchecked")
public void setValue(Object target, Object value) {
accessor.setValue((T) target, (U) value);
}
/**
* Sets the value of this field in a target object
* This method is checked to conform to the generic parameters of the FieldMetadata
*
* @param target The object to set the field of
* @param value The value to set the field to
*/
public void setValueChecked(T target, U value) {
accessor.setValue(target, value);
}
@Override
public String toString() {
return field.getName();
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof FieldMetadata) {
FieldMetadata<?, ?> other = (FieldMetadata<?, ?>) obj;
return Objects.equal(field, other.field);
}
return false;
}
@Override
public int hashCode() {
return Objects.hashCode(field);
}
}