1. Design Patterns in Java and .NET Tim Murphy Technical Specialist Mike Vogt Vice President of Architecture

2. Objective Show the usefulness of Design Patterns when developing applications and how they apply no matter what the platform.

3. Agenda History of patterns What are patterns Why are patterns important Explore 6 common patterns Anti-Patterns

4. History Of Patterns Gang Of Four POSA – Patterns of Software Architecture Patterns of Enterprise Application Architecture

5. What Are Patterns Pattern Name Problem Solution Consequences

6. Why Are Patterns Important Common vocabulary Repositories of common solutions

7. Factory Method Pattern Method for object creation Lets subclasses decide which classes to create

8. Decorator Pattern Attach additional responsibilities to an object dynamically Allows behavior to be added via “wrappers” Avoids extensive inheritance hierarchies cost() Whip cost() Mocha cost() DarkRoast

9. Adapter Pattern Allows a system to use methods that do not match their interface

10. Visitor Pattern A way of separating an algorithm from an object structure it operates on. One can add new operations to existing object structures without modifying those structures <<interface>> CarElement + accept(CarElementVisitor v) Wheel Engine Body Car

11. Strategy Pattern Interchangeable algorithms

12. Composite Pattern Allows you to compose objects into tree structures to represent whole-part hierarchies. Lets clients treat individual objects and compositions of objects uniformly. <<interface>> Component + operation + add(Component c) + remove(Component c) + getChild(inti) Node Client Leaf Leaf Leaf Composite add, remove, getChild, operation Leaf + operation()

13. Anit-Patterns One pattern to rule them all Loosey Goosey

14. ResourcesDesign Patterns: Elements of Reusable Object-Oriented Software – Erich Gamma, Richard Helm, Ralph Johnson, and John VlissidesHead First Design Patterns – Eric Freeman and Elisabeth FreemanDesign Patterns In C# - Steven John Metsker

15. Thank You!Blogs –geekswithblogs.net/tmurphyEmail -tmurphy@psclistens.commvogt@psclistens.comTwitter –@twmurph@mvogt99PSC’s websitewww.psclistens.com