Question

I have a abstract class called Customer which has some attributes shared amongst all customers(ex id, name, surname).

Then I have few classes such as PriorityCustomers which have special unique fields such as(height, width), MidPriorityCustomers etc.

When I do this :

Customer customer = new PriorityCustomer();

I cannot access the priority customer methods. When I try it other way arround I can’t instantiate abstract class.

I’m using this because I want to process all customers trough same process only those who have special needs do something special for them.

My method is therefore returning Customer type. Am I making the wrong decision with the design here? Can anybody suggest something?

Forgot to mention :

Fields that I have in my parent abstract class I don’t have those in special customer classes and the other way arround.(no height, width in Customer class, but those are in PriorityCustomers class)

Answer 1

Its sounds like you have a super process method when you want specific ones.

abstract class Customer {
    public abstract returnType process(args);
}

class PriorityCustomer extends Customer {
    public returnType process(args) {
       // process PriorityCustomer 
    }
}

class MidPriorityCustomer extends Customer {
    public returnType process(args) {
       // process MidPriorityCustomer 
    }
}

Then all you need to is

for(Customer customer: customers)
    customer.process(args);

This will allows you to process all Customer types where each Customer type knows what special processing it needs.