Drools Rule Expression : Access Nested class data member

问题

Below is the structure of my classes:

public class Address {
                private String street;
        private int phone;
        public void setStreet(String s){street = s;}
        public void setPhone(int p){phone = p;}
        public String getStreet(String s){return street;}
        public int getPhone(){  return phone;   }
}
public class Borrower {
    Address adr = new Address();
    public void setAddress(String s, int p) {
        adr.setStreet(s);
        adr.setPhone(p);
    }   
    public Address getAddress() {   return adr; }   
}

Drools Expression I am using :-

rule "Nested Address"
    salience -10    
    when
        $bo : Borrower(Address.street.equals("USA") && Address.phone != 717)
        $loanApp : LoanApplication()        
    then 
        $loanApp.addFeedbackMessage(FeedbackMessages.LOCATION_NOT_US);  
        System.out.println("Nested Address  " + $bo.adr.street + ", Nested Phone " + $bo.adr.phone);
end

Above gives me Error :

Unable to Analyse Expression Address.street.equals("USA"):

Can someone please tell me what I am doing wrong?

回答1:

You should be using "adr" (property name) instead of "Address" (class name):

rule "Nested Address"
    salience -10    
    when
        $bo : Borrower(adr.street.equals("USA") && adr.phone != 717)
        $loanApp : LoanApplication()        
    then 
        $loanApp.addFeedbackMessage(FeedbackMessages.LOCATION_NOT_US);  
        System.out.println("Nested Address  " + $bo.adr.street + ", Nested Phone " + $bo.adr.phone);
end

回答2:

you should be using the property name "address" (notice the lowercase a) and not the class Address. so:

rule "Nested Address"
    salience -10    
    when
        $bo : Borrower(address.street.equals("USA") && address.phone != 717)
        $loanApp : LoanApplication()        
    then 
        $loanApp.addFeedbackMessage(FeedbackMessages.LOCATION_NOT_US);  
        System.out.println("Nested Address  " + $bo.adr.street + ", Nested Phone " + $bo.adr.phone);
end

来源：https://stackoverflow.com/questions/19347545/drools-rule-expression-access-nested-class-data-member

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java

drools