documentation for strategy pattern

tk-codes · web-flow · commit 2f698569b225 · 2016-12-22T23:51:44.000+01:00
diff --git a/BehavioralPatterns/Strategy/README.md b/BehavioralPatterns/Strategy/README.md
@@ -1,3 +1,38 @@
 ﻿# Strategy
 
-The Strategy Pattern defines a family of algorithms, encapsulates each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.
+The Strategy Pattern 
+* defines a family of algorithms, 
+* encapsulates each one, and 
+* make them interchangeable. 
+Strategy lets the algorithm vary independently from clients that use it.
+
+![Duck App with Strategy Pattern](/Diagrams/Strategy.png)
+
+**Usage**
+```cs
+Duck mallard = new MallardDuck();
+mallard.PerformQuack();
+mallard.PerformFly();
+
+// change the flying behavior dynamically
+Duck model = new ModelDuck();
+model.PerformFly(); // default behavior
+model.FlyBehavior = new FlyRocketPowered();  // set a different flying behavior at runtime
+model.PerformFly();
+```
+
+
+## Common Structure
+
+![Common structure of strategy pattern](http://www.dofactory.com/images/diagrams/net/strategy.gif)
+
+* Strategy  (SortStrategy)
+ * declares an interface common to all supported algorithms. Context uses this interface to call the algorithm defined by a ConcreteStrategy
+* ConcreteStrategy  (QuickSort, ShellSort, MergeSort)
+ * implements the algorithm using the Strategy interface
+* Context  (SortedList)
+ * is configured with a ConcreteStrategy object
+ * maintains a reference to a Strategy object
+ * may define an interface that lets Strategy access its data.
+
+_[Source: http://www.dofactory.com/net/strategy-design-pattern]_
