On Sun, Jan 4, 2015 at 2:27 PM, Stuart Douglas <sdouglas_at_redhat.com> wrote:
>
>
> ----- Original Message -----
> > From: "Greg Wilkins" <gregw_at_intalio.com>
> > To: jsr369-experts_at_servlet-spec.java.net
> > Sent: Saturday, 3 January, 2015 4:39:21 AM
> > Subject: [jsr369-experts] Clarify onAllDataRead ?
> >
> > I think we need to clarify when onAllDataRead should be called.
> >
> > My understanding is that once isReady() has returned false, a callback is
> > scheduled:
> >
> > - If the IO that arrives is data, then onDataAvailable() is called.
> > - If the IO that arrives is EOF, then onAllDataRead() is called.
> >
> > But it is possible for the code within onDataAvailable to read, call
> > isReady() and get a true result and then read -1 for the EOF. In that
> > case, should onAllDataRead() be called? If so should it wait until the
> > call to onDataAvailable() has returned?
> >
> > I can see it two ways:
> >
> > Either we have a callback paradigm that is triggered by isReady()==false
> > and that once that occurs there should be one and only one callback to
> > either onDataAvailable or to onAllDataRead()
> >
> > OR
> >
> > onAllDataRead() is a separate callback paradigm to the onDataAvailable
> and
> > will be called regardless once EOF is received.
> >
> > I think the former is simpler to implement, but might cause surprises for
> > application developers who expect it always to be called.
> >
> > The problem with the later is that it means that an onAllDataRead()
> > callback can come even if isReady()!=false. This breaks the fundamental
> > callback paradigm that a callback will only occur if isReady() has called
> > false.
> >
> > thoughts?
> >
>
> My gut feeling is that onAllDataRead should always be called, regardless
> of if a -1 was returned from onDataAvailable.
>
> In this case I think the obvious thing to do is to immediately call
> onAllDataRead after onDataAvailable has finished, regardless of if the user
> has called isReady(). I know this is a slightly different callback
> semantic, but I don't think it really matters.
>
> If you don't call onAllDataRead in all cases then you have a situation
> where a user has to handle EOF in two different places (I know they can
> just delegate to the onAllDataRead method, but it still seems a bit odd).
>
> > As a secondary question, if EOF has arrived, but neither -1 has been read
> > or onAllDataRead() called, should isFinished() return true?
>
> I don't think it should return true until this notification has been
> delivered to the user. Otherwise some layer of code could check this flag
> and take some action based on the isFinished flag, however the read
> listener may not have been notified yet. It also seems counter intuitive
> that callbacks could still be pending when isFinished() returns true.
>
I would expect all the above behavior too.
>
> Stuart
>
> >
> >
> > cheers
> >
> >
> >
> > --
> > Greg Wilkins <gregw_at_intalio.com> @ Webtide - *an Intalio subsidiary*
> > http://eclipse.org/jetty HTTP, SPDY, Websocket server and client that
> scales
> > http://www.webtide.com advice and support for jetty and cometd.
> >
>