JESS: Rule LHS patterns and multiple hierarchical object models.

[Nguyen, Son]

Hi,

My goal is to have logical expressions in rule LHS involving multiple
templates derived from hierarchical Java models:


public class PO {
        public Customer customer;
        // setter, getter not shown.
}

public class Customer {
        public String name;
        public Address address;
        // setters, getters not shown.
}

public class Address {
        public int streetNumber;
        public String street;
        public String city;
        // setters, getters not shown.
}

Templates:

(deftemplate Customer
    (declare (from-class Customer)
                 (include-variables TRUE)))

(deftemplate PO
    (declare (from-class PO)
                 (include-variables TRUE)))


The following rule can handle an expression such as:
If (purchaseOrder.customer.address.street == customer.address.street)


(defrule rule
    (Customer (address ?address))
    (PO (customer ?customer)) 
    (test (= 0 (str-compare ((?customer getAddress) getStreet) (?address
getStreet))))  
    =>
    (bind ?name (?customer getName))
    (bind ?addr (?address getStreet))
    (printout t ?addr ": customer: " ?name crlf)
)

Are there better, more elegant ways to accomplish the same?

I tried:

?po <-  (PO (customer ?customer)) 
?customer <-  (Customer (address ?address))
(test (=  (((?po getCustomer) getAddress) getStreet)  ((?customer
getAddress) getStreet)))

But ?po and ?customer are facts (Jess.Fact) that have no getCustomer and
getAddress methods.


Son