通过UDP并发接收和发送数据

Question

I am trying to write a program that constantly listens for packets over UDP, but also periodically sends out data over UDP (every x seconds). The tricky part is the data I receive will change the data I send out, so I don't think I can simply do one of the tasks in a separate thread. I also can't afford to have any blocking. I was hoping someone could give me a push in the right direction. If it's relevant, I am programming in Java, and will be sending and receiving data with multiple clients at a time.

Answer 1

I don't think I can simply do one of the tasks in a separate thread.

You can still have the recv and send in separate threads. But they cannot happen asynchronously. If the data that you send out is going to depend on the data that you receive, then you cannot have the send/recv asynchronously. This is a request/response model. The response has to be sent only after receving the request.

I also can't afford to have any blocking

You can still have the sockets set for non-blocking

Answer 2

While you could use separate threads, you can do this single-threaded with a simple timeout associated with your socket:

Follow the example here:

set timeout for socket receive

When the socket throws a timeout exception, you do your periodic send, then go back to receiving data on the socket.