RomanNumeral.java

public class RomanNumeral {
	
	Map<String, Integer> numberMap = new HashMap<String, Integer>();
	
	public RomanNumeral() {
		numberMap.put("I", 1);
		numberMap.put("V", 5);
		numberMap.put("X", 10);
		numberMap.put("L", 50);
		numberMap.put("C", 100);
		numberMap.put("D", 1000);		
	}

	public int convert(String numeral) {
		int sum = 0;
		
		int start = numberMap.get(String.valueOf(numeral.charAt(0)));
		int endIndex = numeral.length() - 1;
		int end = numberMap.get(String.valueOf(numeral.charAt(endIndex)));
		
		if (start < end) {
			
			sum = numberMap.get(String.valueOf(numeral.charAt(endIndex)));
			for (int i = numeral.length() - 2; i >= 0; i--) {
				char character = numeral.charAt(i);
				sum -= numberMap.get(String.valueOf(character));
			}
		} else {

			for (int i = 0; i < numeral.length(); i++) {
				char character = numeral.charAt(i);
				sum += numberMap.get(String.valueOf(character));
			}
		}
		return sum;
	}