I'm writing a chess program in Java. The GUI should be able to communicate with a chess engine supporting the Chess Engine Communication Protocol. But I'm having some difficulties reconciling the protocol with Java's I/O facilities.
Because engines that predate protocol version 2 do not send "feature", xboard uses a timeout mechanism: when it first starts your engine, it sends "xboard" and "protover N", then listens for feature commands for two seconds before sending any other commands.
It seems that Java's facilities for interrupting I/O operations are limited. The only option I can find is NIO's InterruptibleChannel, which closes itself when interrupted.
I don't want the stream to close when the timeout occurs -- I just want to interrupt the read. Does anyone know a solution?
I think you may be overthinking the problem. You don't need to abort the read() call after 2 seconds, you just need your backing logic to understand that after 2 seconds it should not expect to receive any "feature" commands. Then your implementation can write the next command, and your read() will return the byte(s) from the response to that command.
That's how I'd approach it anyways, by having generic code that reads in bytes and passes them further up the chain where context-specific processing can be done. Then you don't need to interrupt the read, the upstream code just needs to understand that the data it eventually gets back may be a "feature" command, or it may not be.