16_template method.py

"""
	Template Method
	- a behavioral design pattern that defines the skeleton of an algorithm in the superclass
	but lets subclasses override specific steps of the algorithm without changing its structure.
"""
import abc


class Top(abc.ABC):
	def template_method(self):
		self.first_common()
		self.second_common()
		self.third_require()
		self.fourth_require()

	def first_common(self):
		print('This is first common...')

	def second_common(self):
		print('This is second common...')

	@abc.abstractmethod
	def third_require(self):
		pass

	@abc.abstractmethod
	def fourth_require(self):
		pass


class One(Top):
	def third_require(self):
		print('This is third require from One')

	def fourth_require(self):
		print('This is fourth require from One')


class Two(Top):
	def third_require(self):
		print('This is third require from Two')

	def fourth_require(self):
		print('This is fourth require from Two')


def client(klass):
	klass.template_method()

client(Two())