multithreading - Java Multi thread messaging -

i have app 2 threads, 1 writes queue , second 1 read async it. need create third 1 generate 20 more. newly created threads run till explicitly stopped. 20 threads should "live" data in order analyze it. each of 20 has unique id/name. need send relevant data (that read thread collect) correct thread (of 20 threads). e.g. if data include string id (in it) of 2 --> need send thread id =2. question is: how should hold "pointer" each of 20 threads , send relevant data? (i can search id in runnable list (that hold threads)--> need call method "newdata(string)" in order send data running thread). how should it? tia paz

you better use queue communicate threads. put of queues in map easy access. recommend blockingqueue.

public class test {   // special stop message tell worker stop.   public static final message stop = new message("stop!");    static class message {     final string msg;      // message worker.     public message(string msg) {       this.msg = msg;     }      public string tostring() {       return msg;     }    }    class worker implements runnable {     private volatile boolean stop = false;     private final blockingqueue<message> workqueue;      public worker(blockingqueue<message> workqueue) {       this.workqueue = workqueue;     }      @override     public void run() {       while (!stop) {         try {           message msg = workqueue.poll(10, timeunit.seconds);           // handle message ...            system.out.println("worker " + thread.currentthread().getname() + " got message " + msg);           // special stop message.           if (msg == stop) {             stop = true;           }         } catch (interruptedexception ex) {           // stop on interrupt.           stop = true;         }       }     }   }    map<integer, blockingqueue<message>> queues = new hashmap<>();    public void test() throws interruptedexception {     // keep track of threads.     list<thread> threads = new arraylist<>();     (int = 0; < 20; i++) {       // make queue it.       blockingqueue<message> queue = new arrayblockingqueue(10);       // build thread, handing queue use.       thread thread = new thread(new worker(queue), "worker-" + i);       threads.add(thread);       // store queue in map.       queues.put(i, queue);       // start process.       thread.start();     }      // test one.     queues.get(5).put(new message("hello"));      // close down.     (blockingqueue<message> q : queues.values()) {       // stop each queue.       q.put(stop);     }      // join threads wait them finish.     (thread t : threads) {       t.join();     }   }    public static void main(string args[]) {     try {       new test().test();     } catch (throwable t) {       t.printstacktrace(system.err);     }   }  }