Updating existing JDK code to use InputStream.transferTo()

Chris Hegarty chris.hegarty at oracle.com
Wed May 13 22:40:31 UTC 2015

> On 13 May 2015, at 22:45, Remi Forax <forax at univ-mlv.fr> wrote:
>> may return 0, is when len == 0. And it's never the case here. Unless, of course,
>> some misbehaving implementation of InputStream is used.
> The other reason to have read that returns 0 is if the underlying channel is in non-blocking mode.
> A read on an InputStream created by Channels.newInputStream on a SelectableChannel may return 0
> and the code will go in a loop until the SelectableChannel can read something.
> while(read() > 0) avoid that issue.

Remi, is this right? I’d have to write a simple test to fully satisfy myself, but ChannelInputStream appears to put a SelectableChannel into blocking mode before reading, if it is non-blocking.

> The other things that may be a problem with this patch is that a lot of codes replaced by transferTo use
> either a bigger or a smaller size of buffer than transferTo.
> Given that we don't know if the buffer size is something important for a code or if the buffer size can be changed, i think it's better to split this patch in several parts and to send each parts to the right mailing list.

You are probably right, anything that is not a like for like replacement with the transferTo implementation should have a thorough review from the appropriate component team.


> regards,
> Rémi

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