Update README.md

iluwatar · iluwatar · commit 10216f2ec9fc · 2014-08-24T19:17:45.000+03:00
diff --git a/README.md b/README.md
@@ -86,6 +86,13 @@
 ##Decorator
 **Intent:** Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.
 
+![alt text](https://github.com/iluwatar/java-design-patterns/blob/master/decorator/etc/decorator.jpg "Decorator")
+
+**Applicability:** Use Decorator
+* to add responsibilities to individual objects dynamically and transparently, that is, without affecting other objects
+* for responsibilities that can be withdrawn
+* when extension by subclassing is impractical. Sometimes a large number of independent extensions are possible and would produce an explosion of sublasses to support every combination. Or a class definition may be hidden or otherwise unavailable for subclassing
+
 ##Facade
 **Intent:** Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.
 
