Cocoa Design Patterns

26. Façade

The Façade pattern exists to limit the coupling between objects that interact with a complex subsystem and the objects that implement the complex subsystem. The Façade pattern hides complexity. A real-world example of the Façade pattern is the customer interaction when using the phone to order pizza delivery. As a customer, you typically communicate with just the order taker who answered the phone at the pizza parlor, but there may be many people involved in fulfilling your order. Figure 26.1 illustrates the hypothetical relationships between the people, companies, and services that may contribute toward fulfilling your pizza order.

Figure 26.1 Relationships involved in pizza order fulfillment

As a customer, you don’t normally need ...