Number aware string sorting with comparator

StringWithNumberComparator.java

import java.math.BigInteger;
import java.util.Comparator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class StringWithNumberComparator implements Comparator<CharSequence> {
    public static final StringWithNumberComparator INSTANCE =
            new StringWithNumberComparator();

    private static final Pattern PATTERN = Pattern.compile("(\\D*)(\\d*)");

    private StringWithNumberComparator() {
    }

    public int compare(CharSequence charSequenceOne, CharSequence charSequenceTwo) {
        Matcher matcher1 = PATTERN.matcher(charSequenceOne);
        Matcher matcher2 = PATTERN.matcher(charSequenceTwo);

        while (matcher1.find() && matcher2.find()) {
            int nonDigitCompare = matcher1.group(1).compareTo(matcher2.group(1));
            if (0 != nonDigitCompare) {
                return nonDigitCompare;
            }

            if (matcher1.group(2).isEmpty()) {
                return matcher2.group(2).isEmpty() ? 0 : -1;
            } else if (matcher2.group(2).isEmpty()) {
                return +1;
            }

            BigInteger number1 = new BigInteger(matcher1.group(2));
            BigInteger number2 = new BigInteger(matcher2.group(2));
            int numberCompare = number1.compareTo(number2);
            if (0 != numberCompare) {
                return numberCompare;
            }
        }

        return matcher1.hitEnd() && matcher2.hitEnd() ? 0 :
                matcher1.hitEnd() ? -1 : +1;
    }

    public static void main(String[] args) {
        System.out.println(StringWithNumberComparator.INSTANCE.compare("qwe 7", "qwe 8"));
        System.out.println(StringWithNumberComparator.INSTANCE.compare("qwe 8", "qwe 7"));
        System.out.println(StringWithNumberComparator.INSTANCE.compare("qwe 9", "qwe 10"));
        System.out.println(StringWithNumberComparator.INSTANCE.compare("qwe 20", "qwe 19"));
        System.out.println(StringWithNumberComparator.INSTANCE.compare("qwe 20", "qwe 20"));

    }
}