Question

Can somebody help me with this problem, I dont know why there is an addCustomer() function in the Customer class.

How can a new Customer object be created in a Customer object? The example is as follows:

-------------------
Class Customer     
-------------------
+forename        
+lastname
-------------------
+createCustomer()
-------------------

I mean where is the new Customer obejct stored when there are only those 2 attributes ?

Answer 1

EDIT: updated following comment from Alexander Pavlov below (thanks).

Most likely it’s a factory method. So it’s a class-based operation rather than instance-based. Just like in java/c#/etc where class-based ops (e.g. constructor/factory) and instance-based operations are both declared in the class signature.

As with java etc. the createCustomer() operation would not be called on an instance. e.g. (pseudocode)

Customer customer1 = Customer.createCustomer();
Customer customer2 = Customer.createCustomer();
customer1.forename = "Jon";
customer1.surname  = "Skeet";
//etc.

There used to be a convention in UML that class-based ops start with the ‘$’ symbol to differentiate them from instance-based ops. However, iirc, it was just a convention, not mandated in the UML spec. (don’t have easy access to the spec just now to check).

hth.