Do I have to define a rule or a query to get the name of the instance from the ontology (in a variable)?

Question

My instances have names (screenshot of the said names in Protégé) and slots (image here).

What I need to do is: knowing the value of the slot "DESCRIPTION", getting the name of the instance so I can use it in my Java program.

I thought of a defrule, but does it allow me to have the result in a global variable? Can you please guide me in doing this?

Answer 1

You can indeed use a rule in combination with a global:

(defglobal ?*desc* = "")

Write a rule:

(defrule getDescription
    (SystemEauDeRefroidissement
       (http..#description ?d))
=>
    (bind ?*desc* ?d))

This might work if you have only a single instance of SystemEauDeRefroidissement. You can retrieve the global's value using the Jess API:

Context ctxt = rete.getContext();
Variable var = ctxt.getVariable( "desc" );
String desc = var.stringValue( ctxt );

I haven't tested any of this.

Edit If you have the description, you may write a rule (now more in the Protégé style:

(object
   (is-a http..#SystemEauDeRefroidissement) 
   (OBJECT ?sedr)
   (http..#description ...)
=>
    (bind ?*sedr* ?sedr))

I don't know how you'd like to insert the description value into the Jess environment, so that's why there's the ellipsis.