2:04 p.m.
My team is using Drools on a government project. As is usually the case
with government projects, the security folks have their hands in every
aspect of the project. They have big questions on MVEL, but I'm going to
try to boil them down to one simple question:
At what stage(s) of Drools's lifecycle does MVEL interpretation occur? I
think that the compilation engine interprets the MVEL at compile time and
converts it to generated Java code, though I don't know enough about the
internals of the engine to say for sure. Stated another way, does Drools
interpret rules written using the MVEL dialect at runtime?
Thanks
Mike
1:45 a.m.
Not being an authority on MVEL's usage in Drools, I can't answer your
question. But I'm somewhat surprised about the motives of your "security
folks" to question "runtime interpretation". Therefore, I'll digress
and
highlight a couple of notions. You might discuss them with your boffins.
Take Java. It compiles into byte code, which is interpreted by a JVM (and may
or may not be hotspot compiled at runtime). So, all of your application is
subject to "runtime interpretation".
If you look at the Drools implementation of Rete, you'll find that it represents
rule conditions as a node network, a representation of logic by data. Thus,
any WM updates are (more or less) interpretative.
Compared to these two, any other questions w.r.t. runtime
interpretation rather secondary, don't you think?
-W
On 26/03/2012, Mike Melton <mike.melton(a)gmail.com> wrote:
My team is using Drools on a government project. As is usually the
case
with government projects, the security folks have their hands in every
aspect of the project. They have big questions on MVEL, but I'm going to
try to boil them down to one simple question:
At what stage(s) of Drools's lifecycle does MVEL interpretation occur? I
think that the compilation engine interprets the MVEL at compile time and
converts it to generated Java code, though I don't know enough about the
internals of the engine to say for sure. Stated another way, does Drools
interpret rules written using the MVEL dialect at runtime?
Thanks
Mike
11:40 a.m.
MVEL compiles the string to it's own evaluation tree, it then
"evaluates" that tree at runtime so simulate runtime code. We do a
further optimisation for performance where after MVEL executes a
statement so many times, we'll JIT it to bytecode to get improved
execution performance.
Mark
On 26/03/2012 20:04, Mike Melton wrote:
My team is using Drools on a government project. As is usually the
case with government projects, the security folks have their hands in
every aspect of the project. They have big questions on MVEL, but I'm
going to try to boil them down to one simple question:
At what stage(s) of Drools's lifecycle does MVEL interpretation occur?
I think that the compilation engine interprets the MVEL at compile
time and converts it to generated Java code, though I don't know
enough about the internals of the engine to say for sure. Stated
another way, does Drools interpret rules written using the MVEL
dialect at runtime?
Thanks
Mike
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Wolfgang Laun