スレッドIDを指定して特定のスレッドでメソッドを実行

Question

特定のスレッドIDを知っている場合。次のようにするには？

スレッド。 getThreadById（id）.continueWork（）;

それは可能ですか？

public class Test implements Runnable { 

public void run() { 
    while(true){ 
    pause(); 

    doSomework(); 
    } 
} 

private void doSomework() { 
    System.out.println("do some work"); 
} 

public synchronized void pause() { 
    if (Tester.waitCondition == true) { 
     try { 
      wait(); 
     } catch (InterruptedException e) { 
      e.printStackTrace(); 
     } 
    } 
} 

public synchronized void continueWork() { 
    notify(); 
} 
} 

public class Tester { 

public static boolean waitCondition = true; 

public static void main(String[] args) { 
    Thread nThread = new Thread(new Test()); 
    nThread.start(); 
    waitCondition = false; 
    Thread nThread1 = new Thread(new Test()); 
    nThread1.start(); 
    Thread nThread2 = new Thread(new Test()); 
    nThread2.start(); 
    Thread nThread3 = new Thread(new Test()); 
    nThread3.start(); 

    Long id = nThread.getId(); 
    Thread.getThreadById(id).continueWork(); 


} 
} 

Answer 1

エラボレーション：

public class Tester { 
    // Apologies, I'm too lazy to create two separate files 
    static public class Test implements Runnable { 

    private void doSomework() { 
     System.out.print(
      "do some work on Thread: " 
     +Thread.currentThread().getId() 
    ); 
     try { 
     Thread.sleep(500); // just to simulate a load 
     } 
     catch(InterruptedException e) { 
     // ignore 
     } 
    } 

    public void run() { 
     do { 
     boolean shouldIWait=true; 
     synchronized(Tester.lockingObj) { 
      Boolean flag=Tester.waitConditions.get(Thread.currentThread().getId()); 
      if(null!=flag) { 
      shouldIWait=flag.booleanValue(); 
      } // if null, the tester started me before creating my flag. I'll wait 
      if(shouldIWait) { 
      // I need to wait for someone to wake me 
      try { 
       Tester.lockingObj.wait(); 
      } catch (InterruptedException e) { 
       e.printStackTrace(); 
       // well, I'm interrupted, so I'll do no more work. 
       break; 
      } 
      } 
     } 
     if(false==shouldIWait) { 
      // waiting no more 
      this.doSomework(); 
     } 
     } while(true); 
    } 

    } 

    public static Object lockingObj=new Object(); 

    public static TreeMap<Long, Boolean> waitConditions= 
     new TreeMap<Long, Boolean>(); 

    public static void main(String[] args) { 
    Thread nThread = new Thread(new Test()); 
    Thread nThread1 = new Thread(new Test()); 
    Thread nThread2 = new Thread(new Test()); 
    Thread nThread3 = new Thread(new Test()); 

    // when starting, all threads will be waiting 
    waitConditions.put(nThread.getId(), true); 
    waitConditions.put(nThread.getId(), true); 
    waitConditions.put(nThread.getId(), true); 
    waitConditions.put(nThread.getId(), true); 

    nThread2.start(); 
    nThread1.start(); 
    nThread.start(); 
    nThread3.start(); 

    Long id = nThread.getId(); 
    synchronized (lockingObj) { // when notified, all thread should wakeup 
     waitConditions.put(id, false); // but only nThread will be allowed to doSomeWork 
     lockingObj.notifyAll(); // wake up all the threads. 
           // Those not allowed, will go into 
           // back waiting 
    } 

    try { 
     // just to have the main thread still running for a while 
     Thread.sleep(3000); 
    } catch (InterruptedException e) { 
    } 
    // maybe we want to switch of nThread and start another? 
    synchronized (lockingObj) { 
     waitConditions.put(id, true); 
     waitConditions.put(nThread1.getId(), false); 
     lockingObj.notifyAll(); 
    } 
    try { 
     // just to have the main thread still running for a while 
     Thread.sleep(3000); 
    } catch (InterruptedException e) { 
    } 

    } 
} 

Answer 2

ロックでスレッドをブロックし、ロックの通知メソッドを呼び出してブロックされたスレッドの実行可能を設定する必要があります。
継続するスレッドが複数ある場合は、Conditionが必要です。ブローのように
：

final Lock lock = new ReentrantLock(); 

final Condition condition1 = lock.newCondition(); 
final Condition condition2 = lock.newCondition(); 

Thread t = new Thread() { 
    @Override 
    public void run() { 

    try { 
     lock.lock(); 
     condition1.await(); 
     System.out.println("end cdt1"); 
    } catch (InterruptedException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } finally { 
     lock.unlock(); 
    } 
    } 
}; 

t.start(); 

Thread t1 = new Thread() { 
    @Override 
    public void run() { 

    try { 
     lock.lock(); 
     condition2.await(); 
     System.out.println("end cdt2"); 
    } catch (InterruptedException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } finally { 
     lock.unlock(); 
    } 

    } 
}; 
t1.start(); 

Thread.sleep(1000); 

Thread tt = new Thread() { 
    @Override 
    public void run() { 
    try { 
     lock.lock(); 
     condition1.signal(); 
    } catch (Exception e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } finally { 
     lock.unlock(); 
    } 
    } 
}; 
tt.start(); 

Thread.sleep(2000); 

Thread tt1 = new Thread() { 
    @Override 
    public void run() { 
    try { 
     lock.lock(); 
     condition2.signal(); 
    } catch (Exception e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } finally { 
     lock.unlock(); 
    } 
    } 
}; 
tt1.start();