ABC's features and roles in python

ABC (Abstract Base Class) is a feature provided by Python for supporting abstraction and polymorphism in object-oriented programming. ABC is used to define abstract classes and specify methods that must be implemented by subclasses.

 

Definition of Abstract Classes:
ABC allows the definition of abstract classes. Abstract classes can contain one or more abstract methods and cannot be instantiated directly.

from abc import ABC, abstractmethod

class MyAbstractClass(ABC):
    @abstractmethod
    def my_abstract_method(self):
        pass

 

Definition of Abstract Methods:
Abstract methods can be defined using the @abstractmethod decorator. Subclasses must implement these abstract methods.

Support for Polymorphism:
ABC supports polymorphism, allowing different classes to inherit from the same abstract class and provide a consistent interface by implementing the same methods.

class AnotherClass(ABC):
    @abstractmethod
    def my_abstract_method(self):
        pass

 

Instance Checking and Enforcement:
The "isinstance" function can be used to check whether an object is an instance of a specific abstract class. This allows enforcing the desired interface in the code.

obj = MyConcreteClass()
if isinstance(obj, MyAbstractClass):
    obj.my_abstract_method()

 

Self-Check and Enforcement:
ABC provides self-checking capabilities. If a subclass does not implement an abstract method, attempting to create an instance of that subclass will raise a TypeError.

class MyConcreteClass(MyAbstractClass):
    pass  # Raises TypeError since my_abstract_method is not implemented