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App55 client library for the Java platform.
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/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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.googlecode.openbeans;

import java.lang.reflect.Array;

class ArrayPersistenceDelegate extends PersistenceDelegate
{

	private static PersistenceDelegate	pd	= null;

	public static PersistenceDelegate getInstance()
	{
		if (pd == null)
		{
			pd = new ArrayPersistenceDelegate();
		}
		return pd;
	}

	@Override
	protected Expression instantiate(Object oldInstance, Encoder out)
	{
		assert oldInstance != null && oldInstance.getClass().isArray() : oldInstance;

		int length = Array.getLength(oldInstance);
		Class componentType = oldInstance.getClass().getComponentType();

		return new Expression(oldInstance, Array.class, "newInstance", //$NON-NLS-1$
				new Object[] { componentType, Integer.valueOf(length) });
	}

	@Override
	protected void initialize(Class type, Object oldInstance, Object newInstance, Encoder out)
	{

		assert oldInstance != null && oldInstance.getClass().isArray() : oldInstance;
		assert newInstance != null && newInstance.getClass().isArray() : newInstance;

		int length = Array.getLength(oldInstance);

		for (int i = 0; i < length; ++i)
		{
			Object oldValue = Array.get(oldInstance, i);
			Object newValue = Array.get(newInstance, i);
			if (!deepEquals(oldValue, newValue))
			{
				Statement s = new Statement(oldInstance, "set", //$NON-NLS-1$
						new Object[] { Integer.valueOf(i), oldValue });
				out.writeStatement(s);
			}
		}
	}

	private boolean deepEquals(Object oldInstance, Object newInstance)
	{
		if (oldInstance == newInstance)
		{
			return true;
		}
		if (null == oldInstance || null == newInstance)
		{
			return false;
		}
		// oldInstnace != newInstance
		if (oldInstance.getClass().isAssignableFrom(newInstance.getClass()) && oldInstance.equals(newInstance))
		{
			return true;
		}
		else if (oldInstance.getClass().isArray() && newInstance.getClass().isArray())
		{
			int length1 = Array.getLength(oldInstance);
			int length2 = Array.getLength(newInstance);
			if (length1 != length2)
			{
				return false;
			}
			for (int i = 0; i < length1; i++)
			{
				Object oldValue = Array.get(oldInstance, i);
				Object newValue = Array.get(newInstance, i);
				if (!deepEquals(oldValue, newValue))
				{
					return false;
				}
			}
			return true;
		}
		else
		{
			return false;
		}
	}

	@Override
	protected boolean mutatesTo(Object oldInstance, Object newInstance)
	{
		if (null == oldInstance || null == newInstance)
		{
			return false;
		}

		if (!oldInstance.getClass().isArray() || !newInstance.getClass().isArray())
		{
			return false;
		}

		// both are array
		int l1 = Array.getLength(oldInstance);
		int l2 = Array.getLength(newInstance);
		Class cType1 = oldInstance.getClass().getComponentType();
		Class cType2 = newInstance.getClass().getComponentType();
		if (l1 == l2 && cType1.equals(cType2))
		{
			return true;
		}

		return false;
	}
}