/*
 * Copyright (C) 2004 NNL Technology AB
 * Visit www.infonode.net for information about InfoNode(R) 
 * products and how to contact NNL Technology AB.
 *
 * 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.
 */

// $Id: Enum.java,v 1.8 2005/02/16 11:28:14 jesper Exp $
package net.infonode.util;

import java.io.*;
import java.util.HashMap;

/**
 * Base class for enum classes. Each enum value contains a name and an integer identifier.
 *
 * @author Jesper Nordenberg
 * @version $Revision: 1.8 $ $Date: 2005/02/16 11:28:14 $
 */
public class Enum implements Serializable, Writable {
	private static final long serialVersionUID = 1;
	private static final HashMap VALUE_MAP = new HashMap();

	private int value;
	private transient String name;

	protected Enum(int value, String name) {
		this.value = value;
		this.name = name;

		HashMap values = (HashMap) VALUE_MAP.get(getClass());

		if (values == null) {
			values = new HashMap();
			VALUE_MAP.put(getClass(), values);
		}

		values.put(new Integer(value), this);
	}

	/**
	 * Returns the integer identifier for this enum value.
	 *
	 * @return the integer identifier for this enum value
	 */
	public int getValue() {
		return value;
	}

	/**
	 * Return the name of this enum value.
	 *
	 * @return the name of this enum value
	 */
	public String getName() {
		return name;
	}

	@Override
	public String toString() {
		return name;
	}

	@Override
	public void write(ObjectOutputStream out) throws IOException {
		writeObject(out);
	}

	protected static Object getObject(Class cl, int value) throws IOException {
		HashMap map = (HashMap) VALUE_MAP.get(cl);

		if (map == null)
			throw new IOException("Invalid enum class '" + cl + "'!");

		Object object = map.get(new Integer(value));

		if (object == null)
			throw new IOException("Invalid enum value '" + value + "'!");

		return object;
	}

	private void writeObject(ObjectOutputStream out) throws IOException {
		out.writeShort(value);
	}

	private void readObject(ObjectInputStream in) throws IOException {
		value = in.readShort();
	}

	protected static Object decode(Class cl, ObjectInputStream in) throws IOException {
		return getObject(cl, in.readShort());
	}

	protected Object readResolve() throws ObjectStreamException {
		try {
			return getObject(getClass(), getValue());
		} catch (IOException e) {
			return this;
		}
	}
}
