Static Class Structure

• Invoker
  • Refers to the Command interface to perform a request (command.execute())
    and is independent of how the request is implemented.
  • Maintains a reference (command) to a Command object.
• Command
  • Defines a common interface for performing a request.
• Command1,…
  • Implement the Command interface (for example, by calling action1() on a Receiver1 object).
  • See also Implementation.

Dynamic Object Collaboration

• In this sample scenario, an Invoker object delegates performing a request to a Command object.
  Let's assume that Invoker is configured with a Command1 object.
• The interaction starts with the Invoker object that calls execute() on its installed Command1 object.
• Command1 calls action1() on a Receiver1 object.
• See also Sample Code / Example 1.