##Design Pattern

• Whats is?

"Each pattern describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice" - Christopher Alexander says

• Strategy

###Strategy

Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it. - Gof

###When to use the Strategy?

• When you want to define a class that will have one behavior that is similar to other behaviors in a list:

  • Not flying
  • Flying fasts
  • Flying with rocket

• When you need to use one of severel behaviors dynamically

• Often reduces long lists of conditonals

• Avoid duplicate code

• Keeps class changes from forcing other class changes

• Can hide complicated

###Problem?

• Increased number of Classes.

###UML sample.