StringComparator.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 edu.yu.einstein.genplay.util.Utils;


/**
 * @author Nicolas Fourel
 * @version 0.1
 */
public class StringComparator implements Comparator<String> {


	@Override
	public int compare(String o1, String o2) {
		return compareWords(o1, o2);
	}


	/**
	 * Compares two string taking into account numbers than can be present at the end of each string.
	 * @param s1 first string
	 * @param s2 second string
	 * @return		-1 if s1 is before, 1 if after, 0 if they are equal
	 */
	public int compareWords(String s1, String s2) {
		int index = 0;
		while ((index < s1.length()) && (index < s2.length())) {			// while the index is lower than the length of both string
			String c1 = s1.substring(index, (index + 1));					// gets the character at the current index for the first string
			String c2 = s2.substring(index, (index + 1));					// gets the character at the current index for the second string

			Integer i1 = null;												// Tries to parse the current characters into integer value
			Integer i2 = null;
			try {
				i1 = Integer.parseInt(c1);
			} catch (Exception e) {}
			try {
				i2 = Integer.parseInt(c2);
			} catch (Exception e) {}

			if ((i1 != null) && (i2 != null) ) {							// If both current characters are integer
				Integer i3 = Utils.getFullIntegerPart(s1, index);			// gets the full integer present in the string
				Integer i4 = Utils.getFullIntegerPart(s2, index);

				int compare = i3.compareTo(i4);								// regular integer comparison

				if (compare == 0) {											// if they are equal, string comparison must continue
					index += i3.toString().length();						// the new index continues after the integer
				} else {
					return compare;											// if they are not equal, we return the comparison result
				}

			} else if ((i1 != null) && (i2 == null) ) {						// if there is an integer in the first string but in the second string
				return -1;													// the first string is before
			} else if ((i1 == null) && (i2 != null) ) {						// if there is an integer in the second string but in the first string
				return 1;													// the first string is after
			} else {														// if there is no integer, we continue the scan
				index++;													// increase index by 1
			}

			if ((index >= s1.length()) && (index < s2.length())) {			// if the first string is shorter than the second
				return -1;													// the first string is before
			} else if ((index < s1.length()) && (index >= s2.length())) {	// if the first string is longer than the second
				return 1;													// the first string is after
			}

			int result = c1.compareToIgnoreCase(c2);						// compares characters
			if (result != 0) {												// if they are not equal
				return result;												// we return the result
			}
		}
		return 0;															// if scan is here, both sting are equal.
	}
}