/*
 * The MIT License (MIT)
 * 
 * Copyright (c) 2013 Jeff Nelson, Cinchapi Software Collective
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package org.cinchapi.concourse.server.storage;

import java.util.Comparator;

import com.google.common.primitives.Longs;

/**
 * A Comparator that sorts Revisions in a block. The sort order is
 * {@code locator} followed by {@code key} followed by {@code version}.
 * 
 * @author jnelson
 */
@SuppressWarnings("rawtypes")
public enum BlockSorter implements Comparator<Revision> {
	INSTANCE;

	/**
	 * Sorts by locator followed by key followed by version.
	 */
	@Override
	@SuppressWarnings("unchecked")
	public int compare(Revision o1, Revision o2) {
		int order;
		return (order = o1.getLocator().compareTo(o2.getLocator())) != 0 ? order
				: ((order = o1.getKey().compareTo(o2.getKey())) != 0 ? order
						: (Longs.compare(o1.getVersion(), o2.getVersion())));
	}

}

Make an enum since only one instance should ever exist
Make an enum since only one instance should ever exist
