RxJava2を使い始めたばかりで、UDP観測を正しく実装できるかどうか疑問です。
私はすでにいくつかの作業コードを持っていますが、いくつかの問題があると思います。以下のソースコードのコメントの4つの質問を参照してください。RxJava2 UDPパケットを監視する方法は?
私はGitHub RxJava2_Udpにコードを公開しました。コメント、問題、プルリクエストを歓迎します。
class UdpObservable {
private static class UdpThread extends Thread {
private final int portNo;
private final int bufferSizeInBytes;
private final ObservableEmitter<DatagramPacket> emitter;
private DatagramSocket udpSocket;
private UdpThread(@NonNull ObservableEmitter<DatagramPacket> emitter
, int portNo, int bufferSizeInBytes) {
this.emitter = emitter;
this.portNo = portNo;
this.bufferSizeInBytes = bufferSizeInBytes;
}
@Override
public void run() {
try {
// we don't want to create the DatagramSocket in the constructor, because this
// might raise an Exception that the observer wants to handle
udpSocket = new DatagramSocket(portNo);
try {
/* QUESTION 1:
Do I really need to check isInterrupted() and emitter.isDisposed()?
When the thread is interrupted an interrupted exception will
be raised anyway and the emitter is being disposed (this is what
caused the interruption)
*/
while (!isInterrupted() && !emitter.isDisposed()) {
byte[] rcvBuffer = new byte[bufferSizeInBytes];
DatagramPacket datagramPacket = new DatagramPacket(rcvBuffer, rcvBuffer.length);
udpSocket.receive(datagramPacket);
// QUESTION 1a: same as QUESTION 1 above
if (!isInterrupted() && !emitter.isDisposed()) {
emitter.onNext(datagramPacket);
}
}
} finally {
closeUdpSocket();
}
} catch (Throwable th) {
// the thread will only be interrupted when the observer has unsubscribed:
// so we need not report it
if (!isInterrupted()) {
if (!emitter.isDisposed()) {
emitter.onError(th);
} else {
// QUESTION 2: is this the correct way to handle errors, when the emitter
// is already disposed?
RxJavaPlugins.onError(th);
}
}
}
}
private void closeUdpSocket() {
if (!udpSocket.isClosed()) {
udpSocket.close();
}
}
@Override
public void interrupt() {
super.interrupt();
// QUESTION 3: this is called from an external thread, right, so
// how can we correctly synchronize the access to udpSocket?
closeUdpSocket();
}
}
/**
* creates an Observable that will emit all UDP datagrams of a UDP port.
* <p>
* This will be an infinite stream that ends when the observer unsubscribes, or when an error
* occurs. The observer does not handle backpressure.
* </p>
*/
public static Observable<DatagramPacket> create(final int portNo, final int bufferSizeInBytes) {
return Observable.create(
new ObservableOnSubscribe<DatagramPacket>() {
@Override
public void subscribe(ObservableEmitter<DatagramPacket> emitter) throws Exception {
final UdpThread udpThread = new UdpThread(emitter, portNo, bufferSizeInBytes);
/* QUESTION 4: Is this the right way to handle unsubscription?
*/
emitter.setCancellable(new Cancellable() {
@Override
public void cancel() throws Exception {
udpThread.interrupt();
}
});
udpThread.start();
}
}
);
}
}
に行く必要があります。質問を更新してください。 –
ソースコードのコメント – TmTron