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.
Usage
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();
- 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]