Programming Challenge 1 - ZipString

/**
 * @Author: FamiHug at FAMILUG
 * @Version: 0.5  Tue Aug  2 15:01:54 ICT 2011
 */

public class PRC01CompressString {
    public static void main(String[] args)
    {
        ZipString zs = new ZipString();
        zs.compressString("AAABBCAABDDAFF");
    }
}

class ZipString {
    public void compressString(String input)
    {
        int charCounter = 1;
        char currentChar = input.charAt(0);
        char previousChar;

        for(int i = 1; i < input.length(); i++) {
            previousChar = currentChar;
            currentChar = input.charAt(i);
            if(currentChar == previousChar) {
                charCounter++;
            }
            else {
                if(charCounter != 1)
                    System.out.print(charCounter + "" + previousChar);
                else System.out.print(previousChar);

                charCounter = 1;
            }
        }
        System.out.println(charCounter + "" + currentChar);
        System.out.println();
    }

}