Update README.md

iluwatar · iluwatar · commit d46e560a247e · 2014-08-24T22:43:38.000+03:00
diff --git a/README.md b/README.md
@@ -169,6 +169,13 @@
 ##Mediator
 **Intent:** Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently.
 
+![alt text](https://github.com/iluwatar/java-design-patterns/blob/master/mediator/etc/mediator.jpg "Mediator")
+
+**Applicability:** Use the Mediator pattern when
+* a set of objects communicate in well-defined but complex ways. The resulting interdependencies are unstructured and difficult to understand
+* reusing an object is difficult because it refers to and communicates with many other objects
+* a behavior that's distributed between several classes should be customizable without a lot of subclassing
+
 ##Memento
 **Intent:** Without violating encapsulation, capture and externalize an object's internal state so that the object can be restored to this state later.
 
