BuilderA Creational Design PatternDorit GoldmanOded Sapir

Based on Alex BluhmRensselaer Polytechnic Institute Troy, New-York

Patterns:Abstract FactoryBuilderFactory MethodPrototypeSingleton

Builder Design Pattern :

-Builder

Participants in Builder PatternBuilderConcreteBuilderDirectorProductBuilderConcreteBuilderDirectorProduct

Structure for ParticipantsProductClient

Builder Pattern Interaction

When to use a Builder PatternWhen the algorithm for building a complex object should be independent of the parts that make up the object and how theyre assembledWhen the construction process must allow different representations for the object thats constructedWhen building a composite structural object

Key Consequence of Builder PatternVary a products internal representationIsolates code for construction and representation

Dont forget that the Builder Design Pattern also gives you finer control over the construction process!

How to code a builderAssembly and Construction InterfaceNo abstract class for productsEmpty 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();};

Other Creational PatternsObject CreationAbstract FactoryPrototypeSingletonClass CreationFactory Method

Special ThanksDesign Patterns. Elements of Reusable Object-Oriented SoftwareErich Gamma, Richard Helm, Ralph Johnson, John VlissidesProvider of Design Pattern powerpoint slides online. (http://vik.ktu.lt/moduliai/)Bob the Builder