Command - GoF

command.py

class Command:
  def execute(self):
    raise NotImplementedError()

class Accelerator(Command):
  
  def __init__(self, car):
    self.car = car

  def execute(self):
    self.car.go()

class Brake(Command):
  def __init__(self, car):
    self.car = car

  def execute(self):
    self.car.stop()

class Car:
  def __init__(self):
    self.status = 'stop'

  def go(self):
    if self.status == 'moving':
      print 'The car is moving faster'
    else:
      print 'The car is moving'    
      self.status = 'moving'

  def stop(self):
    if self.status == 'moving':
      print 'The car stops'
      self.status = 'stop'
    else:
      print 'Do nothing'

class Driver:
  def __init__(self, accelerator, brake):
    self.accelerator = accelerator
    self.brake = brake

  def drive(self):
    self.accelerator.execute()

  def stop(self):
    self.brake.execute()

car = Car()
accelerator = Accelerator(car)
brake = Brake(car)
driver = Driver(accelerator, brake)

driver.drive()
driver.drive()
driver.stop()
driver.stop()