> If that is the case, why is the listener required in any scenario?
If the bean's properties are changed by your java code, jess needs to know about it. Unless your java code calls Rete#modify(), not likely, your bean will need to inform jess via the bean's property change events.
alan
>
>
> ----- Original Message -----
> From: <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Friday, May 21, 2004 1:49 PM
> Subject: Re: JESS: Java Beans
>
>
> > I think Brenda K Hamilton wrote:
> > > What I need is to have a Java program, may or may not be a bean,
> > > load Jess and a set of rules and 'pass' some object, a
> DOM document
> > > is a good example, and have the rules process the object.
> For a DOM
> > > document, the processing would take the form of doing a
> left depth
> > > first traversal and extract selected information.
> > >
> > > >From the documentation and examples, it seems like
> objects that are
> > > manipulated by Jess have to provide a change listener and chance
> > > support. Is this correct?
> > >
> >
> > There are two different ways to "manipulate" Java objects
> in Jess. One
> > way is just as in Java -- writing code that calls methods and
> > otherwise does things explicitly. There are no requirements
> at all on
> > such objects.
> >
> > The other thing you can do is pattern-match on objects --
> i.e., write
> > rules that directly react to them. Jess can pattern-match
> objects to
> > the extent that they are JavaBeans -- i.e., only JavaBean-like
> > properties can be matched.
> >
> > PropertyChangeEvent support is not required, but if a Bean doesn't
> > support it, then Jess will be working with a "snapshot" of
> the object
> > -- if code outside of Jess changes a property of such an
> object, Jess
> > won't know about the new value until Rete.reset() or
> > Rete.updateObject() are called. If, on the other hand, a
> Bean support
> > PropertyChangeEvents, then Jess will know immediately when such
> > changes are made.
> >
> > So the answer is no, support for PropertyChangeEvents is
> not required.
> > For static objects, such as a tree of XML nodes, they
> wouldn't matter
> > even if they were there. PropertyChangeEvents are useful when Beans
> > are connected to some time-varying information source
> outside of Jess.
> >
> >
> > ---------------------------------------------------------
> > Ernest Friedman-Hill
> > Science and Engineering PSEs Phone: (925) 294-2154
> > Sandia National Labs FAX: (925) 294-2234
> > PO Box 969, MS 9012 [EMAIL PROTECTED]
> > Livermore, CA 94550 http://herzberg.ca.sandia.gov
> >
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