You're right that there's no direct method you can call to create a
definstance from Java, although the same is true of many other Jess
functions. Instead you can either do something like what you've done
below, or create and use a Funcall object.
First, an improvement on the scheme below that doesn't require a rule!
rete.store("FOO", obj);
rete.executeCommand("(definstance class-name (fetch FOO) dynamic)");
Second, the Funcall approach. First, build the funcall:
Funcall f = new Funcall("definstance", rete);
f.add(new Value("class-name", RU.ATOM));
f.add(new Value(obj));
f.add(new Value("dynamic", RU.ATOM));
Then you can execute it once:
f.execute(rete.getGlobalContext());
Then you can reuse it as many times as necessary:
f.set(newObj, 2); // replace obj with newObj
f.execute(rete.getGlobalContext());
Wrap these last two lines in a method called definstance(Object)
someplace, make f a member of the method's class,and you're all set.
I think Alan Littleford wrote:
> Forgive me if I've missed something obvious but:
>
> I cannot see a way of 'Definstancing' from within a Userfunction --
> the Definstance functionality within Jess seems private. Is this by
> design, or am I just mssing something very obvious? As it is now I
> simply assert a fact 'foo(OBJECT ?obj)' from my user function ( where
> ?obj is the address of my Bean created within my user function) and then
> I have a rule within Jess along the lines of :
>
> (defrule defitup
> ?f<-(foo (OBJECT ?obj))
> =>
> (definstance <?class-name> ?obj dynamic)
> (retract ?f) ;; don't need it any more
> )
>
> which although it works fine seems to be laborious at best. BTW I'm
> using Jess 5.1 (still intending to move to Jess 6 at some point!)
>
> Thanks to anyone who can shed light on this
>
> Alanl
>
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---------------------------------------------------------
Ernest Friedman-Hill
Distributed Systems Research Phone: (925) 294-2154
Sandia National Labs FAX: (925) 294-2234
Org. 8920, MS 9012 [EMAIL PROTECTED]
PO Box 969 http://herzberg.ca.sandia.gov
Livermore, CA 94550
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