* Second example on Abstract methods - 35-abstractclasses-2.py

Author: Vimal

35-abstractclasses-2.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python
+
+# 34-abstractclasses-1.py
+
+# This code snippet talks about Abstract Base Classes (abc).
+
+# The `abc` module provides features to create
+# Abstract Base Classes.
+
+# To create an Abstract Base Class, set the `__metaclass__` magic method
+# to `abc.ABCMeta`. This will mark the respective class as an Abstract
+# Base Class.
+
+# Now, in order to specify the methods which are to be enforced on the
+# child classes, ie.. to create Abstract Methods, we use the decorator
+# @abc.abstractmethod on the methods we need.
+
+# The child class which inherits from an Abstract Base Class can implement
+# methods of their own, but *should always* implement the methods defined in
+# the parent ABC Class.
+
+# NOTE: This code will error out. This is an example on what 
+# happens when a child class doesn't implement the abstract methods
+# defined in the Parent Class.
+
+import abc
+
+
+class My_ABC_Class(object):
+    __metaclass__ = abc.ABCMeta
+
+    @abc.abstractmethod
+    def set_val(self, val):
+        return
+
+    @abc.abstractmethod
+    def get_val(self):
+        return
+
+# Abstract Base Class defined above ^^^
+
+# Custom class inheriting from the above Abstract Base Class, below
+
+
+class MyClass(My_ABC_Class):
+
+    def set_val(self, input):
+        self.val = input
+
+    def hello(self):
+        print("\nCalling the hello() method")
+        print("I'm *not* part of the Abstract Methods defined in My_ABC_Class()")
+
+my_class = MyClass()
+
+my_class.set_val(10)
+print(my_class.get_val())
+my_class.hello()