Command Pattern

Definition

It is a behavioural pattern that encapsulates requests into objects. Thus clients can be parameterized with different requests which can also be queued and logged which allows for undoing actions.

GoF Template

1. Command: This is an interface or abstract class that defines the execute method, which encapsulates a specific action.

2. Concrete Command: These are the concrete implementations of the Command interface, each encapsulating a specific action and maintaining a reference to the object that performs the action (the receiver).

3. Receiver: This is the object that actually performs the action when the execute method of a command is called.

4. Invoker: This is responsible for maintaining a collection of commands and calling their execute methods.