Java的異步方法調用

Question

我已經有做以下工作一個線程：

public class DetectionHandler extends TimerTask { 

@Override 
public void run() { 
bluetoothAddresses = BluetoothModule.scanAddresses(); 
wiFiAddresses = WiFiModule.scanAddresses(); 
...//when scanning is finished, continue work 
} 

我想是掃描平行。所以我認爲我必須異步調用這兩種方法。當掃描完成後，我可以繼續在DetectionHandler類中工作。

我試過BluetoothModule和WiFiModule實現Runnable的方式，但沒有運氣。 Tnx

Answer 1

使用ExecutorService你可以寫這樣的事情：

ArrayList<Callable<Collection<Address>>> tasks = new ArrayList<Callable<Collection<Address>>>(); 
tasks.add(new Callable<Collection<Address>>() { 
    public Collection<Address> call() throws Exception { 
    return BluetoothModule.scanAddresses(); 
    } 
}); 
tasks.add(new Callable<Collection<Address>>() { 
    public Collection<Address> call() throws Exception { 
    return WiFiModule.scanAddresses(); 
    } 
}); 

ExecutorService executorService = Executors.newFixedThreadPool(2); 
List<Future<Collection<Address>>> futures = executorService.invokeAll(tasks); 

Answer 2

從Executors獲取一個ExecutorService並給它一個FutureTask。

然後，您可以通過調用返回的Future上的阻止get（）來等待結果。掃描將平行運行，但您的運行方法（此處顯示）仍將等待掃描完成。

如A位：

 FutureTask<List<Address>> btFuture = 
     new FutureTask<List<Address>>(new Callable<List<Address>>() { 
     public List<Address> call() { 
      return BluetoothModule.scanAddresses(); 
     }}); 
    executor.execute(btFuture); 

    FutureTask<List<Address>> wfFuture = 
     new FutureTask<List<Address>>(new Callable<List<Address>>() { 
     public List<Address> call() { 
      return WifiModule.scanAddresses(); 
     }}); 
    executor.execute(wfFuture); 

    btAddresses = btFuture.get(); // blocks until process finished 
    wifiAddresses = wfFuture.get(); // blocks 

要當心不過，得到的將返回任何調用返回。異常包裝在ExecutionException中。