我如何使我的程序多次成功地追溯命令？

Question

在开始讨论我的问题之前，这里是有关我的问题的程序的简短概述，以便您理解。我的程序与机器人有关，下面代表了我的程序对机器人执行的一些命令。用户输入的命令存储在commandList.size数组中。

L命令表示机器人向左转。
F命令表示机器人向前移动。
T命令表示机器人从以下位置向后追溯命令用户输入到程序中。例如，如果用户已经输入命令“ L COMMAND，R COMMAND”，则用户输入“ T 2”，这将需要使机器人向右转然后向左转，以便向后读取命令数组。 “ T 2”表示回溯前两个命令。

问题

[如果用户让我的机器人左转，则用户输入“ T 1”以追溯先前输入的命令，然后在用户使机器人前进后，键入“ T 2”以追溯前两个命令，程序将停止工作。该程序应使机器人前进，然后向左转，因为这是最后输入的两个命令。需要忽略“ T 1”命令，因为这没有计算在内。如何使我的程序多次成功地追溯命令？

另一个例子

L COMMAND (Turn left)
"T 1" (Retrace the left command - this work)
B COMMAND (Move backwards)
"T 2" (THIS IS WHERE THE PROGRAM STOPS WORKING - the program needs to skip "T 1" and retrace the F command / B command - Here is the issue) you understand?

上面的问题与我在程序中确定的T命令有关。

控制台示例以突出显示该问题-这不起作用。机器人应向后移动并向右移动。 T 1命令应忽略。

>Move robot right 
>T 1 to retrace last step which works
>Backwards command
>T 2 retrace last two commands.

T命令代码

否则，如果（part.length == 2）{

            if (part[0].equals("T") && represents(part[1])) {

                robot.saySomething("Retracing your desired commands");


                int speakingDelay = 3000;
                try {
                    TimeUnit.MILLISECONDS.sleep(speakingDelay);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                int a = Integer.parseInt(part[1]);

                //checking if user has requested more then executed commandList

                if (commandList.size() >= a) {

                    int index = commandList.size() - 1;

                    for (int i = 0; i < a; i++) {

                        commandHistoryList.add(commandList.get(index));

                        index--;

                    }

                    System.out.println(commandHistoryList);

                    limit = commandList.size() - 1;

                    terms = commandList.size() - a - 1;

                } else {

                    System.out.println("limitimun Value exceeded
");

                    invalidInputs++;

                }

            } else {

                System.out.println("Invalid Command
");

                invalidInputs++;

            }

        }

T命令代码的控制台输出

User1999 please enter a command. 
L 2 100
Moving Left

User1999 please enter a command. 
L 2 100
Moving Left

User1999 please enter a command. 
R 2 100
Moving Right

User1999 please enter a command. 
R 2 100
Moving Right

User1999 please enter a command. 
L 2 100
Moving Left

User1999 please enter a command. 
L 2 100
Moving Left

User1999 please enter a command. 
R 2 100
Moving Right

User1999 please enter a command. 
T 3
[R 2 100, L 2 100, L 2 100]
Moving Right
Moving Left
Moving Left

User1999 please enter a command. 
B 2 100
Moving Backwards

User1999 please enter a command. 
B 2 100
Moving Backwards

User1999 please enter a command. 
T 3
[R 2 100, L 2 100, L 2 100, B 2 100, B 2 100, T 3]
Moving Backwards
Moving Backwards
[R 2 100, L 2 100, L 2 100, B 2 100, B 2 100, T 3, B 2 100, B 2 100, T 3]
Moving Backwards
Moving Backwards
[R 2 100, L 2 100, L 2 100, B 2 100, B 2 100, T 3, B 2 100, B 2 100, T 3, B 2 100, B 2 100, T 3]
Moving Backwards
Moving Backwards
[R 2 100, L 2 100, L 2 100, B 2 100, B 2 100, T 3, B 2 100, B 2 100, T 3, B 2 100, B 2 100, T 3, B 2 100, B 2 100, T 3]
Moving Backwards