/*******************************************************************************
 *
 * Copyright (c) 2010-2011 Sonatype, Inc.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: 
 *
 *   
 *     
 *
 *******************************************************************************/ 

package org.hudsonci.utils.id;

import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamAsAttribute;

import java.util.UUID;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Globally Unique IDentifier; backed by {@link UUID}.
 *
 * @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
 * @since 2.1.0
 */
@XStreamAlias("guid")
public class GUID
    implements ID
{
    @XStreamAsAttribute
    private final UUID value;

    public GUID(final UUID value) {
        this.value = checkNotNull(value);
    }

    public GUID(final String value) {
        this(UUID.fromString(value));
    }

    public GUID() {
        this(UUID.randomUUID());
    }

    public UUID getValue() {
        return value;
    }

    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof GUID)) {
            return false;
        }

        GUID that = (GUID) obj;

        return !(value != null ? !value.equals(that.value) : that.value != null);
    }

    @Override
    public int hashCode() {
        return value != null ? value.hashCode() : 0;
    }

    @Override
    public String toString() {
        return value.toString();
    }
}