/* This file is part of the db4o object database http://www.db4o.com

Copyright (C) 2004 - 2011  Versant Corporation http://www.versant.com

db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.

db4o 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, see http://www.gnu.org/licenses/. */
package com.db4o.ext;

/**
 * a unique universal identify for an object. <br><br>The db4o UUID consists of
 * two parts:<br> - an indexed long for fast access,<br> - the signature of the
 * {@link com.db4o.ObjectContainer ObjectContainer} the object was created with.
 * <br><br>Db4oUUIDs are valid representations of objects over multiple
 * ObjectContainers
 */
public class Db4oUUID {

	private final long longPart;
	private final byte[] signaturePart;

	/**
	 * constructs a Db4oUUID from a long part and a signature part
	 *
	 * @param longPart_      the long part
	 * @param signaturePart_ the signature part
	 */
	public Db4oUUID(long longPart_, byte[] signaturePart_) {
		longPart = longPart_;
		signaturePart = signaturePart_;
	}

	/**
	 * returns the long part of this UUID. <br><br>To uniquely identify an object
	 * universally, db4o uses an indexed long and a reference to the 
     * Db4oDatabase object it was created on.
	 *
	 * @return the long part of this UUID.
	 */
	public long getLongPart() {
		return longPart;
	}


	/**
	 * returns the signature part of this UUID. <br><br> <br><br>To uniquely
	 * identify an object universally, db4o uses an indexed long and a reference to
	 * the Db4oDatabase singleton object of the {@link
	 * com.db4o.ObjectContainer ObjectContainer} it was created on. This method
	 * returns the signature of the Db4oDatabase object of the ObjectContainer: the
	 * signature of the origin ObjectContainer.
	 *
	 * @return the signature of the Db4oDatabase for this UUID.
	 */
	public byte[] getSignaturePart() {
		return signaturePart;
	}

	public boolean equals(Object o) {
		if (this == o) return true;
		if (o == null || getClass() != o.getClass()) return false;

		final Db4oUUID other = (Db4oUUID) o;

		if (longPart != other.longPart) return false;
		if (signaturePart == null) {
			return other.signaturePart == null;
		}
		if (signaturePart.length != other.signaturePart.length) {
			return false;
		}
		for (int i = 0; i < signaturePart.length; i++) {
			if (signaturePart[i] != other.signaturePart[i]) {
				return false;
			}
		}
		return true;
	}

	public int hashCode() {
		return (int) (longPart ^ (longPart >>> 32));
	}

	public String toString() {
		StringBuffer sb = new StringBuffer();
		sb.append(getClass().getName());
		sb.append(" sig: ");
		for (int i = 0; i < signaturePart.length; i++) {
			char c = (char) signaturePart[i];
			sb.append(c);
		}
		sb.append(" long: ");
		sb.append(longPart);
		return sb.toString();
	}

}