Roman String to Integer

romanToInt.java

package wcy.leetcode.gist;

/**
 * Created by ChauyanWang on 12/20/14.
 */
public class romanToInt {
    int getInteger(char c) {
        switch (c) {
            case 'i': return 1;
            case 'v': return 5;
            case 'x': return 10;
            case 'l': return 50;
            case 'c': return 100;
            case 'd': return 500;
            case 'm': return 1000;
        }
        return 0;
    }
    public int Solution (String s) {
        if(s == null || s.length() == 0) return 0;
        s = s.toLowerCase();
        int result = 0;
        int index = 0;
        while (index < s.length()) {
            if(index + 1 != s.length()-1 &&
                    getInteger(s.charAt(index)) < getInteger(s.charAt(index+1))) {
                result += getInteger(s.charAt(index-1)) - getInteger(s.charAt(index));
                index += 2;
            } else {
                result += getInteger(s.charAt(index));
                index++;
            }
        }
        return result;
    }
}