Roman to Integer

Given a roman numeral, convert it to an integer.
Input is guaranteed to be within the range from 1 to 3999.
 1 public class Solution {
 2     public int romanToInt(String s) {
 3         // Start typing your Java solution below
 4         // DO NOT write main() function
 5         StringBuffer ss = new StringBuffer(s);
 6         int i,j;
 7         int result = 0;
 8         if(ss.length() == 0) return result;
 9         else if(ss.length() == 1) return romanChar(ss.charAt(0)); 
10         for(i = 0; i < ss.length(); i++){
11             j = i + 1;
12             if(j == ss.length()){
13                 result += romanChar(ss.charAt(i));
14                 break;
15             }
16             if(leftLarger(ss.charAt(i),ss.charAt(j))){
17                 result += romanChar(ss.charAt(i));
18             }
19             else{
20                 result += romanChar(ss.charAt(j)) - romanChar(ss.charAt(i));
21                 i ++;
22                 
23             }
24         }
25         return result;
26     }
27     
28     public int romanChar(char c){
29         if(c == 'I') return 1;
30         else if(c == 'V') return 5;
31         else if(c == 'X') return 10;
32         else if(c == 'L') return 50;
33         else if(c == 'C') return 100;
34         else if(c == 'D') return 500;
35         else if(c == 'M') return 1000;
36         else return -1;
37     }
38     public boolean leftLarger(char a,char b){
39         if(a == 'M') return true;
40         if(a == 'D' && b != 'M') return true;
41         else if(a == 'C' && b != 'M' && b != 'D') return true;
42         else if(a == 'L' && b != 'M' && b != 'D' && b != 'C') return true;
43         else if(a == 'X' && b != 'M' && b != 'L' && b != 'D' && b != 'C' ) return true;
44         else if(a == 'V' && b != 'M' && b != 'X' && b != 'L' && b != 'D' && b != 'C') return true;
45         else if(a == 'I' && b == 'I') return true;
46         else return false;
47     }
48 }