design-patterns-cpp/factory-method

Factory Method

Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses. The pattern has creational purpose and applies to classes where deals with relationships through inheritence ie. they are static-fixed at compile time. In contrast to Abstract Factory, Factory Method contain method to produce only one type of product.

When to use

• a class cant anticipate the class of objects it must create
• a class wants its subclasses to specify the objects it creates
• classes delegate responsibility to one of several helper subclasses, and you want to localize the knowledge of which helper subclass is the delegate