On 31 March 2012 05:46, Remy Maucherat <rmaucher_at_redhat.com> wrote:
> On Fri, 2012-03-30 at 19:23 +0200, Oleksiy Stashok wrote:
>> Once we don't have integer parameter neither in canWrite nor in
>> notifyCanWrite, AFAIU we can guarantee that if canWrite() returned
>> true - next "write" method call (despite the size of the passed data)
>> will not block.
>
> That's what I am doing (and it works). It is necessary IMO since the for
> example char methods of the writer are relatively unpredictable in terms
> of output size. The downside is the resource use, but as you mention,
> regardless of the technique employed, the memory is used until the bytes
> are written.
There is a big difference between the application holding the
reference and the IO layer holding the reference. The application
layer can know if the buffer is shareable or not.
Say I have 100,000 connections and I want to write the same large
string to all of them, then if the application holds the reference,
then it converts the ig string to a ByteBuffer it can pass a
buffer.asReadOnly() to each connection and there is no copy. If the
IO layer holds the reference, then it will have to copy it (all of it
or just the remainder), then we get 100,000 copies of the large
string!