Python Design Patterns - Command Pattern

Command Pattern adds a level of abstraction between actions and includes an object, which invokes these actions.

In this design pattern, client creates a command object that includes a list of commands to be executed. The command object created implements a specific interface.

Following is the basic architecture of the command pattern −

Example - How to implement the command pattern?

We will now see how to implement the design pattern.

main.py

from abc import ABC, abstractmethod

class Command(ABC):
    
    def __init__(self, receiver):
        self.receiver = receiver
    
    def process(self):
        pass

class Implementator(Command):
    
    def __init__(self, receiver):
        self.receiver = receiver

    def process(self):
        self.receiver.perform_action()

class Receiver:
    def perform_action(self):
        print('Receiver performed an action.')

class Invoker:
   
    def command(self, cmd):
        self.cmd = cmd

    def execute(self):
        self.cmd.process()

if __name__ == "__main__":
    
    receiver = Receiver()
    cmd = Implementator(receiver)
    invoker = Invoker()
    invoker.command(cmd)
    invoker.execute()

Output

The above program generates the following output −

Receiver performed an action.

Explanation

The output showcases all the necessary components of command design pattern.