added external design pattern documentation links to behavioural patterns.

pypatterns/behavioral/chain.py

@@ -1,18 +1,12 @@
 from abc import ABCMeta, abstractmethod
 
 
-class ChainException(Exception):
-    """
-    Exception for when a chain link could not handle a request.
-    """
-    pass
-
-
 class ChainLink(object, metaclass=ABCMeta):
     """
     Abstract ChainLink object as part of the Chain of Responsibility pattern.
-    """
 
+    External Chain of Responsibility Pattern documentation: U{https://en.wikipedia.org/wiki/Chain-of-responsibility_pattern}
+    """
     def __init__(self):
         """
         Initialize a new ChainLink instance.
@@ -34,10 +28,7 @@ class ChainLink(object, metaclass=ABCMeta):
 
         @param request: The request to handle.
         """
-        try:
         return self.successor.handle(request)
-        except AttributeError:
-            raise ChainException
 
     @abstractmethod
     def handle(self, request):
@@ -52,8 +43,9 @@ class ChainLink(object, metaclass=ABCMeta):
 class Chain(object, metaclass=ABCMeta):
     """
     Abstract Chain class as part of the Chain of Responsibility pattern.
-    """
 
+    External Chain of Responsibility Pattern documentation: U{https://en.wikipedia.org/wiki/Chain-of-responsibility_pattern}
+    """
     def __init__(self, chainlink):
         """
         Initialize a new Chain instance.
@@ -70,7 +62,7 @@ class Chain(object, metaclass=ABCMeta):
         """
         try:
             return self.chainlink.handle(request)
-        except ChainException:
+        except AttributeError:
             return self.fail()
 
     @abstractmethod

pypatterns/behavioral/command.py

@@ -18,8 +18,9 @@ class InvalidInvokerCommandException(Exception):
 class Receiver(object, metaclass=ABCMeta):
     """
     Abstract receiver class as part of the Command pattern.
-    """
 
+    External Command Pattern documentation: U{https://en.wikipedia.org/wiki/Command_pattern}
+    """
     def action(self, name, *args, **kwargs):
         """
         Delegates which method to be called for a desired action.
@@ -38,8 +39,9 @@ class Receiver(object, metaclass=ABCMeta):
 class Command(object, metaclass=ABCMeta):
     """
     Abstract Command class as part of the Command pattern.
-    """
 
+    External Command Pattern documentation: U{https://en.wikipedia.org/wiki/Command_pattern}
+    """
     def __init__(self, receiver):
         """
         Initialize a new command instance.
@@ -67,8 +69,9 @@ class Command(object, metaclass=ABCMeta):
 class Invoker(object, metaclass=ABCMeta):
     """
     Abstract Invoker class as part of the Command pattern.
-    """
 
+    External Command Pattern documentation: U{https://en.wikipedia.org/wiki/Command_pattern}
+    """
     def __init__(self, valid_commands):
         """
         Initialize a new Invoker instance.

pypatterns/behavioral/interpreter.py

@@ -4,6 +4,8 @@ from abc import ABCMeta, abstractmethod
 class Context(object):
     """
     Context class as part of the Interpreter design pattern.
+
+    External Interpreter Pattern documentation: U{https://en.wikipedia.org/wiki/Interpreter_pattern}
     """
     def __init__(self, in_data):
         """
@@ -18,6 +20,8 @@ class Context(object):
 class Expression(object, metaclass=ABCMeta):
     """
     Abstract Expression class as part of the Interpreter design pattern.
+
+    External Interpreter Pattern documentation: U{https://en.wikipedia.org/wiki/Interpreter_pattern}
     """
     @abstractmethod
     def interpret(self, context):
@@ -33,6 +37,8 @@ class Expression(object, metaclass=ABCMeta):
 class NonTerminalExpression(Expression, metaclass=ABCMeta):
     """
     Base class for the NonTerminalExpression class as part of the Interpreter design pattern.
+
+    External Interpreter Pattern documentation: U{https://en.wikipedia.org/wiki/Interpreter_pattern}
     """
     def __init__(self, **expressions):
         """
@@ -47,6 +53,8 @@ class NonTerminalExpression(Expression, metaclass=ABCMeta):
 class TerminalExpression(Expression, metaclass=ABCMeta):
     """
     Base class for the TerminalExpression class as part of the Interpreter design pattern.
+
+    External Interpreter Pattern documentation: U{https://en.wikipedia.org/wiki/Interpreter_pattern}
     """
     def __init__(self, literal):
         """

pypatterns/behavioral/iterator.py

@@ -4,6 +4,8 @@ from abc import ABCMeta, abstractmethod
 class Iterator(object):
     """
     An Iterator class for the Iterator design pattern.
+
+    External Iterator Pattern documentation: U{https://en.wikipedia.org/wiki/Iterator_pattern}
     """
     def __init__(self, iterable):
         """
@@ -24,6 +26,8 @@ class Iterator(object):
 class Iterable(object, metaclass=ABCMeta):
     """
     An abstract class representing an Iterable object as part of the Iterator design pattern.
+
+    External Iterator Pattern documentation: U{https://en.wikipedia.org/wiki/Iterator_pattern}
     """
     @abstractmethod
     def __next__(self):

pypatterns/behavioral/mediator.py

@@ -4,6 +4,8 @@ from collections import defaultdict
 class Mediator(object):
     """
     Mediator class as part of the Mediator design pattern.
+
+    External Mediator Pattern documentation: U{https://en.wikipedia.org/wiki/Mediator_pattern}
     """
     def __init__(self):
         """
@@ -45,4 +47,3 @@ class Mediator(object):
             self.signals[signal_name].remove(receiver)
         except ValueError:
             pass
-

pypatterns/behavioral/memento.py

@@ -4,6 +4,8 @@ from copy import deepcopy
 class Memento(object):
     """
     Memento class as part of the Memento design pattern.
+
+    External Mediator Pattern documentation: U{https://en.wikipedia.org/wiki/Memento_pattern}
     """
     def __init__(self, state):
         """
@@ -22,6 +24,8 @@ class Memento(object):
 class Originator(object):
     """
     Originator base class as part of the Memento design pattern.
+
+    External Mediator Pattern documentation: U{https://en.wikipedia.org/wiki/Memento_pattern}
     """
     def commit(self):
         """

pypatterns/behavioral/null.py

@@ -1,6 +1,8 @@
 class Null(object):
     """
     A Null object class as part of the Null object design pattern.
+
+    External Null Object Pattern documentation: U{https://en.wikipedia.org/wiki/Null_Object_pattern}
     """
     def __init__(self, *args, **kwargs):
         """

pypatterns/behavioral/observer.py

@@ -4,6 +4,8 @@ from abc import ABCMeta, abstractmethod
 class Observer(object, metaclass=ABCMeta):
     """
     Abstract Observer class as part of the Observer design pattern.
+
+    External Observer Pattern documentation: U{https://en.wikipedia.org/wiki/Observer_pattern}
     """
     @abstractmethod
     def update(self, **state):
@@ -15,7 +17,9 @@ class Observer(object, metaclass=ABCMeta):
 
 class Observable(object):
     """
-    Base Observable class as part of the Observer design pattern
+    Base Observable class as part of the Observer design pattern.
+
+    External Observer Pattern documentation: U{https://en.wikipedia.org/wiki/Observer_pattern}
     """
     def __init__(self):
         """

pypatterns/behavioral/strategy.py

@@ -5,6 +5,8 @@ class Strategy(object):
     """
     An abstract Strategy class.
     All strategies should inherit this class.
+
+    External Strategy Pattern documentation: U{https://en.wikipedia.org/wiki/Strategy_pattern}
     """
     __metaclass__ = ABCMeta
 

pypatterns/behavioral/template.py

@@ -4,6 +4,8 @@ from abc import ABCMeta, abstractmethod
 class Template(object, metaclass=ABCMeta):
     """
     Abstract Template class as part of the Template design pattern.
+
+    External Template Design Pattern Documentation: U{https://en.wikipedia.org/wiki/Template_method_pattern}
     """
     @abstractmethod
     def go(self):

pypatterns/behavioral/visitor.py

@@ -4,6 +4,8 @@ from abc import ABCMeta, abstractmethod
 class Visitor(metaclass=ABCMeta):
     """
     Abstract Visitor class as part of the Visitor Design Pattern.
+
+    External Visitor Design Pattern documentation: U{https://en.wikipedia.org/wiki/Visitor_pattern}
     """
     def visit(self, node, *args, **kwargs):
         """
@@ -39,6 +41,8 @@ class Visitor(metaclass=ABCMeta):
 class Visitee(object):
     """
     A base class for objects that wish to be able to be visited by a Visitor class.
+
+    External Visitor Design Pattern documentation: U{https://en.wikipedia.org/wiki/Visitor_pattern}
     """
     def accept(self, visitor):
         """

tests/behavioral_tests/test_chain.py

@@ -1,6 +1,6 @@
 from unittest import TestCase
 
-from pypatterns.behavioral.chain import ChainException, ChainLink, Chain
+from pypatterns.behavioral.chain import ChainLink, Chain
 
 
 class ChainLinkTestCase(TestCase):
@@ -66,7 +66,7 @@ class ChainLinkTestCase(TestCase):
         @raise AssertionError: If the test fails.
         """
         handler = self.chain_link_one_class()
-        with self.assertRaises(ChainException):
+        with self.assertRaises(AttributeError):
             handler.handle("foo")