On 30 May 2012 16:26, Rajiv Mordani <rajiv.mordani_at_oracle.com> wrote:
>
> Yes that's what we have done. If there are references to
> NonBlockingInputSource and NonBlockingOutputSink in the document then that's
> a bug. We will fix that. But as you point out - since we removed the Readers
> and Writers the necessary methods have just been added to SIS and SOS.
Rajiv,
can you clarify how the output methods are meant to work, as I can't
see how they can be done fully NonBlocking (and may be better named as
Async as Remy suggests).
For example if servletOutputStream.canWrite() returns true, then I
immediately do
out.write(verylargearrayofbytes);
then the signature of write has no way to communicate a partial write
- thus a full write must be done (which is fine). But if that array
is too large to be written without blocking then there are several
ways in which this can be done:
a) The write call will block until all data is written. This would
give us a kind of hybrid mode where small writes could be done
asynchronously, but large ones may block. Benefit of this approach is
that it is simple to implement and simple to use without any complex
buffering.
b) The write will send as much as it can and then copy the unwritten
data and return immediately. It will flush the unwritten data
asynchronously and while doing so canWrite will be false and any
writelistener will be called when the write completes. This gives
nonBlocking behaviour, but at the cost of a potential big copy.
c) The write will send as much as it can and then return immediately
but keep a reference to the data array. It will flush the unwritten
data asynchronously and while doing so CanWrite will be false and any
writelisteners will be called when the write completes. This gives
nonBlocking behaviour, but the caller must not change the passed byte
array until such time as they are told the output stream is writeable
again. However it avoids a large copy. This mode is kind of like
NIO.2 style, but without ByteBuffers.
Also I'm not exactly sure how often WriteListener.onWritePossible is
called? Is it called after every write? ie if I write 1 byte and
there is not blocking will it be called?
Finally, how does asynchronous mode interact with
Response.resetBuffer, Response.setBufferSize etc. When writing
nonBlocking, can we write data < the buffer size and then reset the
buffer?
regards