Re: JESS: Is it possible to bind a Java object directly to a Jess variable without creating a new object?
I daresay, not all of us use the same terms for the same things ;-)
I'll use "Pojo" for a Java object; it contains data in named fields. I'll
use "Fact" for an entitiy that has been inserted into Jess' Working Memory;
it contains data in named slots. And then, there is a "shadow fact", which
is a fact with a reference to a Pojo in a slot that is (by definition)
called OBJECT; slot values are taken from the object's fields of the same
name.
Quote: "I am trying to assert to Jess that an object exists when I
encounter a new object in my Java program."
Comment: In any case, this must be done by creating/inserting a fact. As
has been said, a shadow fact is the easiest way to do this; it's defined
from the backing class, and it is inserted by adding the Pojo. Creating an
equivalent fact implies that all slots must be filled, by hand-coded code,
from the Pojo; there's no further connection between these two, which is
bound to cause additional details.
Quote: "Is there any way to just bind a Java object to a Jess variable
without creating a new Java object?"
Comment: This is not the same thing as "asserting to Jess". You can bind a
Pojo to a Jess variable without inserting/asserting it. But this variable
will not affect the firing of rules.
-W
On 5 November 2011 00:49, Hunter McMillen wrote:
> Thanks for your quick reply. After I manage to get my Java object into
> Jess, can I assert it as a fact? Then have rules lhs match on the existence
> of some object with attributes x, y, and z?
>
> Hunter
>
> On Fri, Nov 4, 2011 at 4:01 PM, Friedman-Hill, Ernest
> wrote:
>
>> **
>> There are (obviously) two options: (a) put the object somewhere
>> accessible, and run Jess code that retrieves it, or (b) use Jess's Java API
>> to set a Jess variable to contain the object. Either would work. The
>> store/fetch mechanism is sort of an built-in easy way to do (a).
>> Alternatively, say there's a global variable ?*x* defined in your Jess
>> program. Then you can say
>>
>> engine.getGlobalContext().setVariable("*x*", new Value(unit));
>>
>> and your Jess code can later get the value of "*x*".
>>
>> If you don't like using variables this way, there's always directly
>> invoking Jess functions from Java. Here we invoke 'add' to add the object
>> to working memory directly:
>>
>> new Funcall("add", engine).arg(new
>> Value(unit)).execute(engine.getGlobalContext());
>>
>>
>>
>> ----------
>> *From:* owner-jess-us...@sandia.gov [mailto:owner-jess-us...@sandia.gov]
>> *On Behalf Of *Hunter McMillen
>> *Sent:* Friday, November 04, 2011 1:08 PM
>> *To:* jess-users
>> *Subject:* JESS: Is it possible to bind a Java object directly to a Jess
>> variable without creating a new object?
>>
>> Hi everyone,
>>
>> I am trying to assert to Jess that an object exists when I encounter a
>> new object in my Java program. Right now I am using a template to mirror
>> that object (i.e I have slot values for all of the Java objects fields)
>> but this seems redundant to me. Is there any way to just bind a Java
>> object to a Jess variable without creating a new Java object?
>>
>> A lot of the examples I see online and from JIA are of the form:
>> (bind ?map (new HashMap))
>>
>> or
>>
>> (call Classname method params...)
>>
>> but these either create a new object or call static methods. I already
>> have the Java object and just want to store it.
>>
>> But I was hoping that there was someway I could do something like this:
>> public Rete engine = new Rete();
>>
>> public void unitDiscovered()
>> {
>> Unit unit = ; //Java object
>> engine.executeCommand("(bind ?unit unit)");
>> engine.executeCommand("(assert ?unit)");
>> }
>>
>> Or would I have to use the store() and fetch() methods for this?
>>
>> public void unitDiscovered()
>> {
>> Unit unit = ; //Java object
>> engine.store("UNIT", unit);
>> engine.executeCommand("(bind ?unit (fetch "UNIT")");
>> engine.executeCommand("(assert ?unit)");
>> }
>>
>> Basically I want to know the best practice for binding Java objects to
>> Jess variables so I can assert them to the engine.
>>
>> Thanks,
>> Hunter McMillen
>>
>>
>
RE: JESS: Is it possible to bind a Java object directly to a Jess variable without creating a new object?
That's what Rete.add() and Rete.definstance() do. If that's the goal, all of
this other stuff is superfluous -- just call add() or definstance() from Java.
From: owner-jess-us...@sandia.gov [mailto:owner-jess-us...@sandia.gov] On
Behalf Of Hunter McMillen
Sent: Friday, November 04, 2011 7:50 PM
To: jess-users
Subject: Re: JESS: Is it possible to bind a Java object directly to a Jess
variable without creating a new object?
Thanks for your quick reply. After I manage to get my Java object into Jess,
can I assert it as a fact? Then have rules lhs match on the existence of some
object with attributes x, y, and z?
Hunter
On Fri, Nov 4, 2011 at 4:01 PM, Friedman-Hill, Ernest
mailto:ejfr...@sandia.gov>> wrote:
There are (obviously) two options: (a) put the object somewhere accessible, and
run Jess code that retrieves it, or (b) use Jess's Java API to set a Jess
variable to contain the object. Either would work. The store/fetch mechanism is
sort of an built-in easy way to do (a). Alternatively, say there's a global
variable ?*x* defined in your Jess program. Then you can say
engine.getGlobalContext().setVariable("*x*", new Value(unit));
and your Jess code can later get the value of "*x*".
If you don't like using variables this way, there's always directly invoking
Jess functions from Java. Here we invoke 'add' to add the object to working
memory directly:
new Funcall("add", engine).arg(new
Value(unit)).execute(engine.getGlobalContext());
From: owner-jess-us...@sandia.gov<mailto:owner-jess-us...@sandia.gov>
[mailto:owner-jess-us...@sandia.gov<mailto:owner-jess-us...@sandia.gov>] On
Behalf Of Hunter McMillen
Sent: Friday, November 04, 2011 1:08 PM
To: jess-users
Subject: JESS: Is it possible to bind a Java object directly to a Jess variable
without creating a new object?
Hi everyone,
I am trying to assert to Jess that an object exists when I encounter a new
object in my Java program. Right now I am using a template to mirror that
object (i.e I have slot values for all of the Java objects fields) but this
seems redundant to me. Is there any way to just bind a Java object to a Jess
variable without creating a new Java object?
A lot of the examples I see online and from JIA are of the form:
(bind ?map (new HashMap))
or
(call Classname method params...)
but these either create a new object or call static methods. I already have
the Java object and just want to store it.
But I was hoping that there was someway I could do something like this:
public Rete engine = new Rete();
public void unitDiscovered()
{
Unit unit = ; //Java object
engine.executeCommand("(bind ?unit unit)");
engine.executeCommand("(assert ?unit)");
}
Or would I have to use the store() and fetch() methods for this?
public void unitDiscovered()
{
Unit unit = ; //Java object
engine.store("UNIT", unit);
engine.executeCommand("(bind ?unit (fetch "UNIT")");
engine.executeCommand("(assert ?unit)");
}
Basically I want to know the best practice for binding Java objects to Jess
variables so I can assert them to the engine.
Thanks,
Hunter McMillen
Re: JESS: Is it possible to bind a Java object directly to a Jess variable without creating a new object?
Use "shadow" facts.
see http://www.jessrules.com/jesswiki/view?FactsVsShadowFacts
On Nov 4, 2011, at 1:08 PM, Hunter McMillen wrote:
> Hi everyone,
>
> I am trying to assert to Jess that an object exists when I encounter a new
> object in my Java program. Right now I am using a template to mirror that
> object (i.e I have slot values for all of the Java objects fields) but this
> seems redundant to me. Is there any way to just bind a Java object to a Jess
> variable without creating a new Java object?
>
> A lot of the examples I see online and from JIA are of the form:
> (bind ?map (new HashMap))
>
> or
>
> (call Classname method params...)
>
> but these either create a new object or call static methods. I already have
> the Java object and just want to store it.
>
> But I was hoping that there was someway I could do something like this:
> public Rete engine = new Rete();
>
> public void unitDiscovered()
> {
> Unit unit = ; //Java object
> engine.executeCommand("(bind ?unit unit)");
> engine.executeCommand("(assert ?unit)");
> }
>
> Or would I have to use the store() and fetch() methods for this?
>
> public void unitDiscovered()
> {
> Unit unit = ; //Java object
> engine.store("UNIT", unit);
> engine.executeCommand("(bind ?unit (fetch "UNIT")");
> engine.executeCommand("(assert ?unit)");
> }
>
> Basically I want to know the best practice for binding Java objects to Jess
> variables so I can assert them to the engine.
>
> Thanks,
> Hunter McMillen
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Re: JESS: Is it possible to bind a Java object directly to a Jess variable without creating a new object?
Thanks for your quick reply. After I manage to get my Java object into
Jess, can I assert it as a fact? Then have rules lhs match on the existence
of some object with attributes x, y, and z?
Hunter
On Fri, Nov 4, 2011 at 4:01 PM, Friedman-Hill, Ernest wrote:
> **
> There are (obviously) two options: (a) put the object somewhere
> accessible, and run Jess code that retrieves it, or (b) use Jess's Java API
> to set a Jess variable to contain the object. Either would work. The
> store/fetch mechanism is sort of an built-in easy way to do (a).
> Alternatively, say there's a global variable ?*x* defined in your Jess
> program. Then you can say
>
> engine.getGlobalContext().setVariable("*x*", new Value(unit));
>
> and your Jess code can later get the value of "*x*".
>
> If you don't like using variables this way, there's always directly
> invoking Jess functions from Java. Here we invoke 'add' to add the object
> to working memory directly:
>
> new Funcall("add", engine).arg(new
> Value(unit)).execute(engine.getGlobalContext());
>
>
>
> --
> *From:* owner-jess-us...@sandia.gov [mailto:owner-jess-us...@sandia.gov] *On
> Behalf Of *Hunter McMillen
> *Sent:* Friday, November 04, 2011 1:08 PM
> *To:* jess-users
> *Subject:* JESS: Is it possible to bind a Java object directly to a Jess
> variable without creating a new object?
>
> Hi everyone,
>
> I am trying to assert to Jess that an object exists when I encounter a
> new object in my Java program. Right now I am using a template to mirror
> that object (i.e I have slot values for all of the Java objects fields)
> but this seems redundant to me. Is there any way to just bind a Java
> object to a Jess variable without creating a new Java object?
>
> A lot of the examples I see online and from JIA are of the form:
> (bind ?map (new HashMap))
>
> or
>
> (call Classname method params...)
>
> but these either create a new object or call static methods. I already
> have the Java object and just want to store it.
>
> But I was hoping that there was someway I could do something like this:
> public Rete engine = new Rete();
>
> public void unitDiscovered()
> {
> Unit unit = ; //Java object
> engine.executeCommand("(bind ?unit unit)");
> engine.executeCommand("(assert ?unit)");
> }
>
> Or would I have to use the store() and fetch() methods for this?
>
> public void unitDiscovered()
> {
> Unit unit = ; //Java object
> engine.store("UNIT", unit);
> engine.executeCommand("(bind ?unit (fetch "UNIT")");
> engine.executeCommand("(assert ?unit)");
> }
>
> Basically I want to know the best practice for binding Java objects to
> Jess variables so I can assert them to the engine.
>
> Thanks,
> Hunter McMillen
>
>
RE: JESS: Is it possible to bind a Java object directly to a Jess variable without creating a new object?
There are (obviously) two options: (a) put the object somewhere accessible, and
run Jess code that retrieves it, or (b) use Jess's Java API to set a Jess
variable to contain the object. Either would work. The store/fetch mechanism is
sort of an built-in easy way to do (a). Alternatively, say there's a global
variable ?*x* defined in your Jess program. Then you can say
engine.getGlobalContext().setVariable("*x*", new Value(unit));
and your Jess code can later get the value of "*x*".
If you don't like using variables this way, there's always directly invoking
Jess functions from Java. Here we invoke 'add' to add the object to working
memory directly:
new Funcall("add", engine).arg(new
Value(unit)).execute(engine.getGlobalContext());
From: owner-jess-us...@sandia.gov [mailto:owner-jess-us...@sandia.gov] On
Behalf Of Hunter McMillen
Sent: Friday, November 04, 2011 1:08 PM
To: jess-users
Subject: JESS: Is it possible to bind a Java object directly to a Jess variable
without creating a new object?
Hi everyone,
I am trying to assert to Jess that an object exists when I encounter a new
object in my Java program. Right now I am using a template to mirror that
object (i.e I have slot values for all of the Java objects fields) but this
seems redundant to me. Is there any way to just bind a Java object to a Jess
variable without creating a new Java object?
A lot of the examples I see online and from JIA are of the form:
(bind ?map (new HashMap))
or
(call Classname method params...)
but these either create a new object or call static methods. I already have
the Java object and just want to store it.
But I was hoping that there was someway I could do something like this:
public Rete engine = new Rete();
public void unitDiscovered()
{
Unit unit = ; //Java object
engine.executeCommand("(bind ?unit unit)");
engine.executeCommand("(assert ?unit)");
}
Or would I have to use the store() and fetch() methods for this?
public void unitDiscovered()
{
Unit unit = ; //Java object
engine.store("UNIT", unit);
engine.executeCommand("(bind ?unit (fetch "UNIT")");
engine.executeCommand("(assert ?unit)");
}
Basically I want to know the best practice for binding Java objects to Jess
variables so I can assert them to the engine.
Thanks,
Hunter McMillen
JESS: Is it possible to bind a Java object directly to a Jess variable without creating a new object?
Hi everyone,
I am trying to assert to Jess that an object exists when I encounter a new
object in my Java program. Right now I am using a template to mirror that
object (i.e I have slot values for all of the Java objects fields) but
this seems redundant to me. Is there any way to just bind a Java object to
a Jess variable without creating a new Java object?
A lot of the examples I see online and from JIA are of the form:
(bind ?map (new HashMap))
or
(call Classname method params...)
but these either create a new object or call static methods. I already
have the Java object and just want to store it.
But I was hoping that there was someway I could do something like this:
public Rete engine = new Rete();
public void unitDiscovered()
{
Unit unit = ; //Java object
engine.executeCommand("(bind ?unit unit)");
engine.executeCommand("(assert ?unit)");
}
Or would I have to use the store() and fetch() methods for this?
public void unitDiscovered()
{
Unit unit = ; //Java object
engine.store("UNIT", unit);
engine.executeCommand("(bind ?unit (fetch "UNIT")");
engine.executeCommand("(assert ?unit)");
}
Basically I want to know the best practice for binding Java objects to Jess
variables so I can assert them to the engine.
Thanks,
Hunter McMillen
