added abstract factory pattern

pypatterns/creational/factory.py

@@ -3,11 +3,10 @@ from abc import abstractmethod, ABCMeta
 
 class Factory(object, metaclass=ABCMeta):
     """
-    Abstract Factory Class.
+    Factory Interface.
 
     All Factories should inherit this class and overwrite the create method.
     """
-
     @abstractmethod
     def create(self, **kwargs):
         """
@@ -19,3 +18,37 @@ class Factory(object, metaclass=ABCMeta):
         """
         pass
 
+
+class AbstractFactory(object):
+    """
+    Abstract Factory Class.
+    """
+    def __init__(self):
+        """
+        Initialize the abstract factory.
+
+        Concrete implementations should call this from within their own __init__ method
+        and register all their factories to keys using the register method.
+        """
+        self._factories = dict()
+
+    @abstractmethod
+    def create(self, **kwargs):
+        """
+        Abstract create method.
+
+        Concrete implementations should return a new instance of an object by calling the appropriate factory.
+
+        @param kwargs: Arguments for object creation.
+        """
+        pass
+
+    def _register(self, key, factory):
+        """
+        Register a factory to a key.
+
+        @param key: Key for identifying which factory to use.
+        @type key: str
+        @param factory: The factory to register to the key.
+        """
+        self._factories[str(key)] = factory()