1. Builder A Creational Design Pattern A Presentation by Alex Bluhm And

2. What are Creational Design Patterns?

3. Creational Design Patterns Abstract instantiation process Flexibility in what’s created, who creates it, how it’s created and when Patterns: –Abstract Factory –Builder –Factory Method –Prototype –Singleton

4. Builder Design Pattern Separates the construction of a complex object from its representation Same construction process can create different representations Bob says… Builders specify abstract interfaces for creating parts of a Product object

5. Participants in Builder Pattern Builder ConcreteBuilder Director Product Builder ConcreteBuilder Director Product

6. ConcreteBuilder buildPartA() buildPartB() getResult() Director construct() Builder buildPartA() buildPartB() Client for all parts in structure { builder->buildPart() } Structure for Participants

7. Builder Pattern Interaction aClientaDirectoraConcreteBuilder new ConcreteBuilder new Director(aConcreteBuilder) construct() buildPartA() buildPartB() buildPartC() getResult()

8. When to use a Builder Pattern When the algorithm for building a complex object should be independent of the parts that make up the object and how they’re assembled When the construction process must allow different representations for the object that’s constructed When building a composite structural object

9. Key Consequence of Builder Pattern Vary a product’s internal representation Isolates code for construction and representation Don’t forget that the Builder Design Pattern also gives you finer control over the construction process!

10. How to code a builder Assembly and Construction Interface No abstract class for products Empty methods as default in Builder Class MazeBuilder { Public: virtual void BuildMaze() { } virtual void BuildRoom(int room) { } virtual void BuildDoor(int roomFrom, int roomTo) { } virtual Maze* GetMaze() { return 0;} Protected: MazeBuilder(); };

11. Other Creational Patterns Object Creation –Abstract Factory –Prototype –Singleton Class Creation –Factory Method

12. Special Thanks Design Patterns. Elements of Reusable Object-Oriented Software –Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides Provider of Design Pattern powerpoint slides online. (http://vik.ktu.lt/moduliai/) Bob the Builder