Separate registry per python version

gyermolenko · gyermolenko · commit 37e48a78b5e4 · 2019-03-07T12:27:43.000+02:00
diff --git a/README.md b/README.md
@@ -46,7 +46,7 @@ __Behavioral Patterns__:
 | [memento](patterns/behavioral/memento.py) | generate an opaque token that can be used to go back to a previous state |
 | [observer](patterns/behavioral/observer.py) | provide a callback for notification of events/changes to data |
 | [publish_subscribe](patterns/behavioral/publish_subscribe.py) | a source syndicates events/data to 0+ registered listeners |
-| [registry](patterns/behavioral/registry.py) | keep track of all subclasses of a given class |
+| [registry](patterns/behavioral/registry__py3.py) | keep track of all subclasses of a given class |
 | [specification](patterns/behavioral/specification.py) |  business rules can be recombined by chaining the business rules together using boolean logic |
 | [state](patterns/behavioral/state.py) | logic is organized into a discrete number of potential states and the next state that can be transitioned to |
 | [strategy](patterns/behavioral/strategy.py) | selectable operations over the same data |
diff --git a/patterns/behavioral/registry.py b/patterns/behavioral/registry.py
diff --git a/patterns/behavioral/registry__py2.py b/patterns/behavioral/registry__py2.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+
+class RegistryHolder(type):
+
+    REGISTRY = {}
+
+    def __new__(cls, name, bases, attrs):
+        new_cls = type.__new__(cls, name, bases, attrs)
+        """
+            Here the name of the class is used as key but it could be any class
+            parameter.
+        """
+        cls.REGISTRY[new_cls.__name__] = new_cls
+        return new_cls
+
+    @classmethod
+    def get_registry(cls):
+        return dict(cls.REGISTRY)
+
+
+class BaseRegisteredClass(object):
+    """
+    Any class that will inherits from BaseRegisteredClass will be included
+    inside the dict RegistryHolder.REGISTRY, the key being the name of the
+    class and the associated value, the class itself.
+    """
+    __metaclass__ = RegistryHolder
+
+
+def main():
+    """
+    Before subclassing
+    >>> sorted(RegistryHolder.REGISTRY)
+    ['BaseRegisteredClass']
+
+    >>> class ClassRegistree(BaseRegisteredClass):
+    ...    def __init__(self, *args, **kwargs):
+    ...        pass
+
+    After subclassing
+    >>> sorted(RegistryHolder.REGISTRY)
+    ['BaseRegisteredClass', 'ClassRegistree']
+    """
+
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod(optionflags=doctest.ELLIPSIS)
diff --git a/patterns/behavioral/registry__py3.py b/patterns/behavioral/registry__py3.py
@@ -0,0 +1,49 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+
+class RegistryHolder(type):
+
+    REGISTRY = {}
+
+    def __new__(cls, name, bases, attrs):
+        new_cls = type.__new__(cls, name, bases, attrs)
+        """
+            Here the name of the class is used as key but it could be any class
+            parameter.
+        """
+        cls.REGISTRY[new_cls.__name__] = new_cls
+        return new_cls
+
+    @classmethod
+    def get_registry(cls):
+        return dict(cls.REGISTRY)
+
+
+class BaseRegisteredClass(metaclass=RegistryHolder):
+    """
+    Any class that will inherits from BaseRegisteredClass will be included
+    inside the dict RegistryHolder.REGISTRY, the key being the name of the
+    class and the associated value, the class itself.
+    """
+
+
+def main():
+    """
+    Before subclassing
+    >>> sorted(RegistryHolder.REGISTRY)
+    ['BaseRegisteredClass']
+
+    >>> class ClassRegistree(BaseRegisteredClass):
+    ...    def __init__(self, *args, **kwargs):
+    ...        pass
+
+    After subclassing
+    >>> sorted(RegistryHolder.REGISTRY)
+    ['BaseRegisteredClass', 'ClassRegistree']
+    """
+
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod(optionflags=doctest.ELLIPSIS)
