private void push(Operation op, Stack<Operation> stack) {
        if (stack.size() >= MAX_NR_OF_OPERATIONS) {
            stack.remove(0);
        }
        stack.push(op);
    }
private void push(Operation op, Stack<Operation> stack) {
        if (stack.size() >= MAX_NR_OF_OPERATIONS) {
            stack.remove(0);
        }
        stack.push(op);
    }
private void push ( Operation op , Stack < Operation > stack ) { if ( stack . size ( ) >= MAX_NR_OF_OPERATIONS ) { stack . remove ( 0 ) ; } stack . push ( op ) ; }
****************************************** Private Methods *******************************************
****************************************** Private Methods *******************************************