/*
* ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
* Copyright (C) 2012 Kristian S. Stangeland
*
* This program is free software; you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with this program;
* if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA
*/
package com.comphenix.protocol.reflect.cloning;
import com.comphenix.protocol.reflect.ObjectWriter;
import com.comphenix.protocol.reflect.StructureModifier;
import com.comphenix.protocol.reflect.instances.InstanceProvider;
import com.comphenix.protocol.reflect.instances.NotConstructableException;
/**
* Represents a class capable of cloning objects by deeply copying its fields.
*
* @author Kristian
*/
public class FieldCloner implements Cloner {
protected Cloner defaultCloner;
protected InstanceProvider instanceProvider;
// Used to clone objects
protected ObjectWriter writer;
/**
* Constructs a field cloner that copies objects by reading and writing the internal fields directly.
* @param defaultCloner - the default cloner used while copying fields.
* @param instanceProvider - used to construct new, empty copies of a given type.
*/
public FieldCloner(Cloner defaultCloner, InstanceProvider instanceProvider) {
this.defaultCloner = defaultCloner;
this.instanceProvider = instanceProvider;
// Remember to clone the value too
this.writer = new ObjectWriter() {
@Override
protected void transformField(StructureModifier<Object> modifierSource,
StructureModifier<Object> modifierDest, int fieldIndex) {
defaultTransform(modifierDest, modifierDest, getDefaultCloner(), fieldIndex);
}
};
}
/**
* Default implementation of the field transform. Applies a clone operation before a field value is written.
* @param modifierSource - modifier for the original object.
* @param modifierDest - modifier for the new cloned object.
* @param defaultCloner - cloner to use.
* @param fieldIndex - the current field index.
*/
protected void defaultTransform(StructureModifier<Object> modifierSource,
StructureModifier<Object> modifierDest, Cloner defaultCloner, int fieldIndex) {
Object value = modifierSource.read(fieldIndex);
modifierDest.write(fieldIndex, defaultCloner.clone(value));
}
@Override
public boolean canClone(Object source) {
if (source == null)
return false;
// Attempt to create the type
try {
return instanceProvider.create(source.getClass()) != null;
} catch (NotConstructableException e) {
return false;
}
}
@Override
public Object clone(Object source) {
if (source == null)
throw new IllegalArgumentException("source cannot be NULL.");
Object copy = instanceProvider.create(source.getClass());
// Copy public and private fields alike. Skip static fields.
writer.copyTo(source, copy, source.getClass());
return copy;
}
/**
* Retrieve the default cloner used to clone the content of each field.
* @return Cloner used to clone fields.
*/
public Cloner getDefaultCloner() {
return defaultCloner;
}
/**
* Retrieve the instance provider this cloner is using to create new, empty classes.
* @return The instance provider in use.
*/
public InstanceProvider getInstanceProvider() {
return instanceProvider;
}
}