public void evaluatePrefixMethod(PrefixExpression expression) {
   int type = expression.getOperation().getType();
   switch (type) {
     case Types.PLUS_PLUS:
       evaluatePrefixMethod(type, "next", expression.getExpression(), expression);
       break;
     case Types.MINUS_MINUS:
       evaluatePrefixMethod(type, "previous", expression.getExpression(), expression);
       break;
   }
 }