AsynchronousSocketChannel still throws unspecified exception

[Alan Bateman]

cowwoc wrote:
> :
> I'm a bit confused. Why does
> http://download.oracle.com/javase/7/docs/api/java/nio/channels/AsynchronousSocketChannel.html
> still read "All methods that accept timeout parameters treat values less
> than or equal to zero to mean that the I/O operation does not timeout"? This
> looks like the final JDK7 documentation.
>
> To me, "does not timeout" means "waits forever". Is this a simple
> documentation bug?
>   
The read/write operations in this API are asynchronous. They are not 
synchronous and do not wait, irrespective of the timeout values. So when 
it says "does not timeout" it just means that the I/O operations do not 
have an associated timeout. If you invoke the read/write methods then 
the methods will complete immediately but the I/O operation will only 
complete when bytes are actually read or written (so exactly the same as 
the read/write methods that AsynchronousByteChannel defines).

> :
>   
> Fortunately, that's not what I meant. Looking at
> AsynchronousSocketChannelImpl I am asking for similar handling as
> "!hasSpaceToRead". If timeout <= 0 and we're returning a Future, set the
> value immediately and return the Future. If timeout <= 0 and we're returning
> a CompletionHandler, use Invoker.invoke() to fire an already-computed
> response.
>   
This requires a result, which is why I suggested it would require 
polling the socket and if not readable (or writable, depending) then the 
I/O operation would complete with a result of 0 (which is essentially an 
asynchronous equivalent of synchronous read/write with the channel 
configured non-blocking).

> Does the existing implementation behave this way? Would it be a simple
> matter to add this?
>   
No, it doesn't work this way and would require some consideration before 
going down that route.

-Alan.