Socket I/P stream's read fails to throw IOException when connection is lost

Question

Hi,
Socket.getInputStream().readShort() blocks till it reads from the server. It throws an IOException if the connection is lost before calling the method. But it is not throwing an IOException if the connection is lost after blocking.
That is....
// If the connection is lost before calling, it is throwing an IOException.
short s = mySocket.getInputStream().readShort();
// But, while it is blocked and if I shutdown the server, it's never throwing
// an IOException and it stays blocked.How should I get around this problem?
Thank you!

Answer 1

It's true; a timeout is really the best way.
One approach I thought about using, where I was in control of the protocol, was to periodically send a "nop" type operation to the socket; a message that doesn't do anything. Obviously not all applications have this liberty, either because you aren't in control of the protocol, or because you want to keep your application single threaded. It's also kind of hackish, and not as good as the timeout mechanism in most respects.
You also have to be a little careful about what you define as a "connection failure". If, for example, you set up a TCP/IP socket without a timeout, and then physically disconnect the ethernet cable, the connection will in fact stay up. If you come back an hour later and plug in the cable again, the connection will still be there and will pass traffic again.