Factory Method Pattern

The Factory Method Pattern

Intent: To define an interface for creating an object. But we let subclasses decide which class to instantiate. The factory method lets class defer instantiation to a subclass.

When to use

• A class can not anticipate the object it must create
• A class wants its subclasses to determine the objects they create

Participants:

1. The product. In our example this is the abstract class Pizza
2. The concrete product. In our example these are the sub-classes that extend Pizza
3. The creator. In our example this is the abstract class PizzaStore. It contains an abstract createPizza() method that subclasses must implement.
4. The concrete creator: Returns a concrete product.