public Object calculate(Context context, Queue<Object> rpn) {
        ec.setContext(context);
        LinkedList<Object> operand = OperatorTree(rpn);
        return calculate(operand);
    }
public Object calculate(Context context, Queue<Object> rpn) {
        ec.setContext(context);
        LinkedList<Object> operand = OperatorTree(rpn);
        return calculate(operand);
    }
public Object calculate ( Context context , Queue < Object > rpn ) { ec . setContext ( context ) ; LinkedList < Object > operand = OperatorTree ( rpn ) ; return calculate ( operand ) ; }
根据逆波兰表达式进行计算
根据逆波兰表达式进行计算