Do we need to cancel listener on exit?

[tdroxler]

Hi everyone,

quick question, I'm starting my server with the startListening function and get back the Future[Void]. When my server receive the exit notification (after the obvious shutdown), do I need to cancel or clean in any other way my listnener (the Future[Void])?

Thx

[pisv]

Hi @tdroxler,

You need to call cancel(true) on the future to close the StreamMessageProducer, which will break the loop in the StreamMessageProducer.listen method.

lsp4j/org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/json/ConcurrentMessageProcessor.java

Lines 69 to 78 in 3c98376

	public boolean cancel(boolean mayInterruptIfRunning) {
	if (mayInterruptIfRunning && messageProducer instanceof Closeable) {
	try {
	((Closeable) messageProducer).close();
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}
	return result.cancel(mayInterruptIfRunning);
	}

HTH

[pisv]

See also #585.

[tdroxler]

Thx for your quick answer, I guess I'll go with something like (pseudo code and scala):

  override def exit(): Unit = {
    server.listener.cancel(true)
    if(server.shutdownReceived) {
      System.exit(0)
    } else {
      System.exit(1)
    }
  }

checking the shutdownReceived to follow the exit specs

[pisv]

LGTM 👍