/** Case-reverse. Upper -> lower AND lower -> upper.
    * @param s string
    * @return processed string
    */
   public static String reverseCase (String s) {
	   StringBuffer result = new StringBuffer();
	   for (int i=0; i < s.length(); i++){
		   char ch = s.charAt(i);
		   if (Character.isUpperCase(ch)){
			   result.append(Character.toLowerCase(ch));
		   } else {
			   result.append(Character.toUpperCase(ch));
		   }
	   }
	   return result.toString();
   }