command

Command Pattern

The Command Pattern encapsulates a request as an object, thereby letting you parameterize other objects with different requests, queue or log requests, and support undoable operations.

Structure

classDiagram
class Command {
    << interface>>
    Execute()
}

class Invoker {
    Invoke()
}

class ConcreteCommand {
    Execute()
}

class Receiver {
    Action()
}

ConcreteCommand --|> Command : implements
ConcreteCommand --> Receiver : has-a
Invoker --> Command : has-a

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Working example

As a working example I've implemented a RemoteControl that is meant to be generic, accepting instructions passed in as a Command object. The RemoteControl knows nothing about the action being executed, as the Command object abstracts the call to the Receiver. The RemoteControl only needs to call Execute() on the Command passed in.

The remote control has 7 slots, each slot accepts a "on" and a "off" command. There's also a global Undo() method to allow to take back the last command executed. For implementation details, please have a look at the HomeAutomationInc directory.