How to implement an event listener in the background of the main program in java?

Question

Hi, newbie, so sorry for my question if that sounds naive.

I want to implement a thread that runs in the background and is constantly listening. Listening to what I mean, let's say it continues to check the value returned from the main thread, and if the vaue value exceeds a certain digit, it executes some method or says it quits the program.

If you could give me some idea or at least refer to something useful, that would be great.

Answer 1

You do not want this thread to run in a loop, continuously checking the value, because it could recycle the waste treatment.

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Answer 2

Java ( concurrency Java, ). ( , ).

Answer 3

, java.util.concurrent, @Piotr. , :

import java.util.concurrent.*;

class Main{
    public static void main(String[] args) throws Exception{
        //Create a service for executing tasks in a separate thread
        ExecutorService ex = Executors.newSingleThreadExecutor();
        //Submit a task with Integer return value to the service
        Future<Integer> otherThread = ex.submit(new Callable<Integer>(){
            public Integer call(){
                //do you main logic here
                return 999;//return the desired result
            }
        }

        //you can do other stuff here (the main thread)
        //independently of the main logic (in a separate thread)

        //This will poll for the result from the main
        //logic and put it into "result" when it available
        Integer result = otherTread.get();

        //whatever you wanna do with your result
    }
}

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Answer 4

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Answer 5

action listner is what you are looking for. look here http://download.oracle.com/javase/1.4.2/docs/api/java/awt/event/ActionListener.html