sun.nio.ch.DirectBuffer and jdk9/jigsaw

[Alan Bateman]

On 22/02/2017 14:06, Vitaly Davidovich wrote:

> :
>
> Yes, I know it's never been supported.  That's been fine and it has 
> worked well ... until jigsaw came into the picture.  So my real 
> question is really whether there can be a proper/supported API, with 
> good performance characteristics, that would give access to the base 
> address of a direct bytebuffer.  In other words, can we make the 
> notion of a direct bytebuffer first class? That notion would carry the 
> base address with it (amongst whatever else is deemed worthwhile).
>
> NewDirectByteBuffer is used on the JNI side already, but I need 
> something at the Java level to get the base address so that field 
> offsets can be calculated for reading data using Unsafe (yes, another 
> performance hack because officially supported Java variants currently 
> don't JIT well enough).  The use case is a "view" of native memory, 
> attached to a DBB, used for IPC.
>
If you are using NewDirectByteBuffer already then couldn't you use a map 
of ByteBuffer -> address?

-Alan