On Tuesday, 18 April 2017 at 18:09:54 UTC, Thomas Brix Larsen
"Cap’n Proto is an insanely fast data interchange format and
capability-based RPC system. Think JSON, except binary. Or
think Protocol Buffers, except faster."
The features below, from the capnproto.org description, interest
me. However a MappedByteBuffer would be used for the mmap
feature in java.
mmap: Read a large Cap’n Proto file by memory-mapping it. The OS
won’t even read in the parts that you don’t access.
Inter-language communication: Calling C++ code from, say, Java or
Python tends to be painful or slow. With Cap’n Proto, the two
languages can easily operate on the same in-memory data structure.
Inter-process communication: Multiple processes running on the
same machine can share a Cap’n Proto message via shared memory.
No need to pipe data through the kernel. Calling another process
can be just as fast and easy as calling another thread.
This info from stackoverflow also seems to imply that
MappedByteBuffer would be required for some of the capnproto
features. So, could you explain a little more about what are the
capabilities of the current d library implementation, with just
the ByteBuffer implemented from the java nio code? Thanks, Jay
'If you are willing to consider using a different protocol
framework, Cap'n Proto is extremely similar in design to
Protobufs but features in the ability to read only the part of
the message you care about. Cap'n Proto incurs no overhead for
the fields you don't examine, other than obviously the bandwidth
and memory to receive the raw message bytes. If you are reading
from a file, and you use memory mapping (MappedByteBuffer in
Java), then only the parts of the message you actually use will
be read from disk.'