Re: Low-latency alternative to Java Object Serialization
Tom Anderson wrote:
Lew wrote:
Use JAXB to generate the classes used to process that schema and
incorporate those classes into the protocol at both ends.
Fast, standard and fairly low effort and low maintenance, assuming you=
have version control and continuous integration (CI).
By "fast" I mean both to develop and to operate.
Interesting. I do not believe this to be true. Specifically, i believe
that: (a) developing an XML-based transfer format using JAXB will take
considerably more effort than using standard serialization, or an equally=
convenient library such as JBoss Serialization, although still not a larg=
e
amount of effort, certainly; (b) the data will be larger than
with standard serialization (because the "object graph overhead" is not=
actually that large, and XML is much less space-efficient than
serialization's binary format); and (c) the speed of operation, even
assuming an infinitely fast network, will be lower.
One get-out clause: for very short streams (one or a few objects), XML
might beat standard serialization for space and speed. Standard
serialization does have some per-class overhead, which is
disproportionately expensive for short streams.
Well, I haven't measured, but let's to a little gedankenexperiment.
Fast to develop - serialization is actually tricky to do right. You can us=
e the absolute defaults, but the world is littered with projects that had m=
aintenance issues because serialization was done simple-mindedly. /Effecti=
ve Java/ devotes an entire chapter to the topic. JAXB solutions, and I've =
made several, are very straightforward. Most of the effort goes into schem=
a design, which is parallel to modeling so not even an overhead. I do thin=
k JAXB wins, but on balance assess that a competent programmer could do eit=
her one well with more-or-less similar effort.
Fast to perform - XML is fast enough. Compressed, its bandwidth is not egr=
egious. Overall I/O considerations should dominate, but I'll take a slight=
loss for the safety benefits of JAXB.
--
Lew