Rate-limit calls to an IRC bot

Question

I am working on a IRC bot that has the command !Scouter and it will generate a random number.... I already have that done, what I wanted to make was a cool down system to keep from people spamming it over and over again.

here is my code.

public class Twitchbot extends PircBot {
    Random dice = new Random();
    int number;

    for(int counter=1; counter<=1;counter++) {
        number = 1+dice.nextInt(9001);
        System.out.println(number + " ");
    }

    public Twitchbot() {
        this.setName("Blah");
    }

    public void onMessage(String channel, String sender, String login, String hostname, String message) {
       if (message.equalsIgnoreCase("!Scouter")) {
           sendMessage(channel,": The time is now " + sender + number);
           for(int counter=1; counter<=1;counter++) {
              number = 1+dice.nextInt(9001);
              System.out.println(number + " ");
              try {
                 Thread.sleep(5000);
              } catch(InterruptedException ex) {
                Thread.currentThread().interrupt();
              }
           }
       }
    }
}

I tried using this code for a cool down

 try {
    Thread.sleep(5000);
 } catch(InterruptedException ex) {
     Thread.currentThread().interrupt();
 }

but all it did is do the code after 5 seconds of sleeping. I don't want the command !Scouter to register during that cool down. is there a better way of doing it?

Answer 1

The problem is that onMessage is called asynchronously, so you cannot prevent it from being called with a sleep.

The easiest workaround is to store the current time as an instance variable, and return immediately in onMessage if the difference between the stored time and the current time is less than 5 seconds.

Answer 2

You could save the current system-time on a successfull call using:

lastCall = System.currentTimeMillis();

and before, you check

if(System.currentTimeMillis() - lastCall >= DELAY)

where DELAY is a time in milliseconds (1 second equals 1000 milliseconds).

if that statement is true, set lastCall to the current time:

lastCall = System.currentTimeMillis();

and call the normal code.

---

It would look something like this:

long lastCall = 0L; //Initializing 

public void onMessage(String channel, String sender,
        String login, String hostname, String message) {

   if (message.equalsIgnoreCase("!Scouter")) {
       if(System.currentTimeMillis() - lastCall >= 5000)
       {
           lastCall = System.currentTimeMillis(); // Set lastCall again
           sendMessage(channel,": The time is now " + sender + number);
           for(int counter=1; counter<=1;counter++) {
             number = 1+dice.nextInt(9001);
             System.out.println(number + " ");
           }
       }
   }
}

Answer 3

I don't fully understand the functionality of your system, but I see that your system gets stuck everytime it enters on Sleep.

If you want to get rid of this behavior, a good approach would be to use a Thread as an anonymous class call, and do the things in background.

I would do it like this:

if (message.equalsIgnoreCase("!Scouter")) {
            sendMessage(channel,": The time is now " + sender + number);
            new Thread() {
                @Override
                public void run() {
                    for(int counter=1; counter<=1;counter++) {
                        number = 1+dice.nextInt(9001);
                        System.out.println(number + " ");
                        try {
                            sleep(5000);
                        } catch(InterruptedException ex) {
                            Thread.currentThread().interrupt();
                        }
                    }
                }
            }.run();
        }

Hope it helps.