implemented mediator design pattern

pypatterns/behavioral/mediator.py

@@ -0,0 +1,48 @@
+from collections import defaultdict
+
+
+class Mediator(object):
+    """
+    Mediator class as part of the Mediator design pattern.
+    """
+    def __init__(self):
+        """
+        Initialize a new Mediator instance.
+        """
+        self.signals = defaultdict(list)
+
+    def signal(self, signal_name, *args, **kwargs):
+        """
+        Send a signal out to all connected handlers.
+
+        @param signal_name: The name of the signal.
+        @type signal_name: Str
+        @param args: Positional arguments to send with the signal.
+        @param kwargs: Keyword arguments to send with the signal.
+        """
+        for handler in self.signals[signal_name]:
+            handler(*args, **kwargs)
+
+    def connect(self, signal_name, receiver):
+        """
+        Connect a receiver to a signal.
+
+        @param signal_name: The name of the signal to connect the receiver to.
+        @type signal_name: str
+        @param receiver: A handler to call when the signal is sent out.
+        """
+        self.signals[signal_name].append(receiver)
+
+    def disconnect(self, signal_name, receiver):
+        """
+        Disconnect a receiver from a signal.
+
+        @param signal_name: The name of the signal to disconnect the receiver from.
+        @type signal_name: str
+        @param receiver: The receiver to disconnect from the signal.
+        """
+        try:
+            self.signals[signal_name].remove(receiver)
+        except ValueError:
+            pass
+