ExecutorService停止並等待另一個ExecutorService在Java中完成

Question

我有兩個ExecutorService實例：一個有4個線程，另一個有20個線程。我希望在點擊按鈕時，服務1停止並等待服務2結束。之後，服務1繼續運行。

我試着用wait和notify要做到這一點，但它不是按預期工作：

的ExecutorService 1：

public void readFile(JTextArea textArea) { 
    try { 
     File file = new File(this.fm.fullPath); 
     if (!file.exists()) { 
      return; 
     } 
     BufferedReader br = new BufferedReader(new FileReader(this.fm.fullPath)); 

     ExecutorService executor = Executors.newFixedThreadPool(main.TOTALSTRINGS); 

     String line = br.readLine(); 

     int i=1; 
     while (line != null) { 
      powThread t = new powThread("Thread" + (i+1), line, textArea); 
      executor.execute(t); 
      line = br.readLine(); 
      i++; 
     } 

     executor.shutdown(); 
     Thread t = new Thread() { 
      public void run() { 
       try { 
        executor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS); 
        br.close(); 
       } catch (Exception e) { 

       } 
      } 
     }; 
     t.start(); 

    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
} 

ExecutorService2：

public void generateNumStrings(JTextArea textArea) { 
    StringGenerator sg = new StringGenerator(); 

    int[] dynamicThreads = main.calcThreadsTotal(); 
    int totalThreads = dynamicThreads.length; 

    ExecutorService executor = Executors.newFixedThreadPool(totalThreads); 

    for(int i=0; i<totalThreads; i++) { 
     generateThread t = new generateThread("Thread" + (i+1), sg, dynamicThreads[i], this.fm); 
     executor.execute(t); 
    } 

    executor.shutdown(); 

    Thread t = new Thread() { 
     public void run() { 
      try { 
       textArea.setText(""); 
       executor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS); 
       textArea.append("File write successfully!"); 
      } catch (InterruptedException e) { 

      } 
     } 
    }; 
    t.start(); 
} 

Answer 1

可以使用在一個AtomicReference第一個ExecutorService包裝第二個ExecutorService或第二個如果引用非空，則尚未實例化，則awaitTermination。我假設readFile和generateNumStrings是在同一個班，如果沒有，那麼你就需要找到一些方法，使AtomicReference可見generateNumStrings

private final AtomicReference<ExecutorService> ref = new AtomicReference<>(null); 

private void awaitTermination() throws InterruptedException { 
    ExecutorService executor = ref.get(); 
    if(executor != null) { 
     executor.awaitTermination(1, TimeUnit.DAYS); 
    } 
} 

public void readFile(JTextArea textArea) { 
... 
    while (line != null) { 
     awaitTermination(); 
     powThread t = new powThread("Thread" + (i+1), line, textArea); 
     executor.execute(t); 
     line = br.readLine(); 
     i++; 
    } 
... 
} 

public void generateNumStrings(JTextArea textArea) { 
... 
    ExecutorService executor = Executors.newFixedThreadPool(totalThreads); 
    ref.set(executor); 
... 
}