雖然其他人建議的阻塞隊列可以工作,但我並不是很喜歡它,因爲它需要忙於等待(消費者循環無限輪詢消息)。另一種選擇是在每次Observer
收到通知時提交任務。
public class Main extends Observable implements Observer {
private final int numCores = Runtime.getRuntime().availableProcessors();
private final ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(numCores);
public Main() {
addObserver(this);
}
public static void main(String[] args) throws InterruptedException {
new Main().execute();
}
private void execute() {
for (int i = 0; i < 5; ++i) {
this.setChanged();
this.notifyObservers(i);
try {
Thread.sleep(1000l);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
executor.shutdown();
}
@Override
public void update(Observable o, Object arg) {
System.out.printf("Received notification on thread: %s.\n", Thread.currentThread().getName());
executor.submit(() -> System.out.printf("Running in thread: %s, result: %s.\n",
Thread.currentThread().getName(), arg));
}
}
輸出:
Received notification on thread: main.
Running in thread: pool-1-thread-1, result: 0.
Received notification on thread: main.
Running in thread: pool-1-thread-2, result: 1.
Received notification on thread: main.
Running in thread: pool-1-thread-3, result: 2.
Received notification on thread: main.
Running in thread: pool-1-thread-4, result: 3.
Received notification on thread: main.
Running in thread: pool-1-thread-5, result: 4.
使用的BlockingQueue。當update()被調用時發送隊列中的事件。從run()中的BlockingQueue中讀取事件。 –