CharSequenceComparator.java

/**
 * File: $HeadURL: https://hdt-java.googlecode.com/svn/trunk/hdt-java/src/org/rdfhdt/hdt/util/string/CharSequenceComparator.java $
 * Revision: $Rev: 200 $
 * Last modified: $Date: 2013-04-17 23:36:44 +0100 (mi, 17 abr 2013) $
 * Last modified by: $Author: mario.arias $
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Contacting the authors:
 *   Mario Arias:               mario.arias@deri.org
 *   Javier D. Fernandez:       jfergar@infor.uva.es
 *   Miguel A. Martinez-Prieto: migumar2@infor.uva.es
 */

package org.rdfhdt.hdt.util.string;

import java.util.Comparator;

/**
 * @author mario.arias
 *
 */
public final class CharSequenceComparator implements Comparator<CharSequence> {

	private static final Comparator<CharSequence> instance = new CharSequenceComparator();

	public static Comparator<CharSequence> getInstance() {
		return instance;
	}
		
	/* (non-Javadoc)
	 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
	 */
	@Override
	public int compare(CharSequence s1, CharSequence s2) {
		if(s1==s2) {
			return 0;
		}
		
		if(s1 instanceof DelayedString) {
			s1 = ((DelayedString) s1).str;
		}
		
		if(s2 instanceof DelayedString) {
			s2 = ((DelayedString) s2).str;
		}
		
		if(s1 instanceof CompactString && s2 instanceof CompactString) {
			CompactString cs1 = (CompactString) s1;
			CompactString cs2 = (CompactString) s2;
			return cs1.compareTo(cs2);
		}
		
		if(s1 instanceof String && s2 instanceof String) {
			String rs1 = (String) s1;
			String rs2 = (String) s2;
			return rs1.compareTo(rs2);
		}
		
		if(s1 instanceof ReplazableString && s2 instanceof ReplazableString) {
			ReplazableString cs1 = (ReplazableString) s1;
			ReplazableString cs2 = (ReplazableString) s2;
			return cs1.compareTo(cs2);
		}
		
		// Slower but safe
		
		return s1.toString().compareTo(s2.toString());
//		
//		int len1 = s1.length();
//        int len2 = s2.length();
//        int n = Math.min(len1, len2);
//
//        int k = 0;
//        while (k < n) {
//            char c1 = s1.charAt(k);
//            char c2 = s2.charAt(k);
//            if (c1 != c2) {
//                return c2 - c1;
//            }
//            k++;
//        }
//        return len2 - len1;
	}

}