ListComparator.java

/*******************************************************************************
 * GenPlay, Einstein Genome Analyzer
 * Copyright (C) 2009, 2014 Albert Einstein College of Medicine
 * 
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 * Authors: Julien Lajugie <julien.lajugie@einstein.yu.edu>
 *          Nicolas Fourel <nicolas.fourel@einstein.yu.edu>
 *          Eric Bouhassira <eric.bouhassira@einstein.yu.edu>
 * 
 * Website: <http://genplay.einstein.yu.edu>
 ******************************************************************************/
package edu.yu.einstein.genplay.core.comparator;

import java.util.Comparator;
import java.util.List;


/**
 * @author Nicolas Fourel
 * @version 0.1
 * @param <K>
 */
public class ListComparator<K> implements Comparator<List<K>> {

	private int result = -10;

	/**
	 * @param o1	the first list
	 * @param o2	the second list
	 * @return		true if lists are different (null lists possible), false otherwise
	 */
	public boolean areDifferent (List<K> o1, List<K> o2) {
		int result = compare(o1, o2);
		if ((result > 0) || (result == -1) || (result == -2)) {
			return true;
		}
		return false;
	}


	/**
	 * @param o1	the first list
	 * @param o2	the second list
	 * @return		true if lists are different (null lists impossible), false otherwise
	 */
	public boolean areDifferentNonNull (List<K> o1, List<K> o2) {
		int result = compare(o1, o2);
		if (result > 0) {
			return true;
		}
		return false;
	}


	@Override
	/**
	 * This method compares two lists but uses special code meaning:
	 * 
	 * 0: both lists are equal
	 * 
	 * 1: lists are different
	 * 2: first list is bigger than the second list
	 * 3: first list is smaller than the second list
	 *
	 * -1: the first list if not null but the second list is null
	 * -2: the first list if null but the second list is not null
	 * -3: both lists are null
	 * 
	 * @param o1 first list
	 * @param o2 second list
	 * @return	the integer code
	 */
	public int compare(List<K> o1, List<K> o2) {
		result = perform(o1, o2);
		return result;
	}


	/**
	 * @return the message associated to the error code
	 */
	public String getErrorCode () {
		switch (result) {
		case 0:
			return "Both lists are equal.";
		case 1:
			return "Lists are different.";
		case 2:
			return "First list is bigger than the second list.";
		case 3:
			return "First list is smaller than the second list.";
		case -1:
			return "The first list if not null but the second list is null.";
		case -2:
			return "The first list if null but the second list is not null.";
		case -3:
			return "Both lists are null.";
		default:
			return "Comparison never happend.";
		}
	}


	/**
	 * Compares both list.
	 * @param o1 first list
	 * @param o2 second list
	 * @return	the integer code
	 */
	private int perform (List<K> o1, List<K> o2) {
		if ((o1 == null) && (o2 == null)) {
			return -3;
		} else if ((o1 == null) && (o2 != null)) {
			return -2;
		} else if ((o1 != null) && (o2 == null)) {
			return -1;
		} else {
			if (o1.size() > o2.size()) {
				return 2;
			} else if (o1.size() < o2.size()) {
				return 3;
			} else {
				for (K k: o1) {
					if (!o2.contains(k)) {
						return 1;
					}
				}
				return 0;
			}
		}
	}

}