renamed package to pypattyrn

pypattyrn/behavioral/null.py

@@ -0,0 +1,75 @@
+class Null(object):
+    """
+    A Null object class as part of the Null object design pattern.
+
+    - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Behavioral-Pattern-Usage}
+    - External Null Object Pattern documentation: U{https://en.wikipedia.org/wiki/Null_Object_pattern}
+    """
+    def __init__(self, *args, **kwargs):
+        """
+        Do nothing.
+        """
+        pass
+
+    def __call__(self, *args, **kwargs):
+        """
+        Do nothing.
+
+        @return: This object instance.
+        @rtype: Null
+        """
+        return self
+
+    def __getattr__(self, name):
+        """
+        Do nothing.
+
+        @return: This object instance.
+        @rtype: Null
+        """
+        return self
+
+    def __setattr__(self, name, value):
+        """
+        Do nothing.
+
+        @return: This object instance.
+        @rtype: Null
+        """
+        return self
+
+    def __delattr__(self, name):
+        """
+        Do nothing.
+
+        @return: This object instance.
+        @rtype: Null
+        """
+        return self
+
+    def __repr__(self):
+        """
+        Null object string representation is the empty string.
+
+        @return: An empty string.
+        @rtype: String
+        """
+        return ''
+
+    def __str__(self):
+        """
+        Null object string representation is the empty string.
+
+        @return: An empty string.
+        @rtype: String
+        """
+        return ''
+
+    def __bool__(self):
+        """
+        Null object evaluates to False.
+
+        @return: False.
+        @rtype: Boolean
+        """
+        return False