Pro Design Patterns in Swift

Chapter    20

The Command Pattern

The command pattern provides a mechanism by which details of how to invoke a method can be encapsulated so that the method can be invoked later or by a different component. Table 20-1 puts the command pattern into context.

Table 20-1. Putting the Command Pattern into Context

Question	Answer
What is it?	The command pattern is used to encapsulate details of how to invoke a method on an object in a way that allows the method to be invoked at a different time or by a different component.
What are the benefits?	There are lots of situations in which using a command is useful, but the most common ones are supporting undo operations and creating macros.
When should you use this pattern?	Use this pattern when you want to allow ...