1. By James Sheets

2. An object creational pattern. Separates the construction of a complex object from its representation so that the same construction process can create different representations.

3. 1. An object requires different representations in different contexts 2. How a complex object is constructed is important 3. You need to encapsulate the logic behind constructing a complex object

4.  Convert an internal object into various file formats (pdf, doc)  Building a maze. Create a map, start point, end point, and then the maze walls.

5. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder

6. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder Product: the object being built

7. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder Builder: determines what gets built

8. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder Builder: determines what gets built A different concrete builder for every variation of the product

9. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder Builder: determines what gets built A different concrete builder for every variation of the product Concrete builder provides an interface to retrieve the product

10. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder Director: determines how it’s built

11. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder Director: determines how it’s built Constructor takes a Builder object

12. Director Constructor() Builder BuildPart() : void ConcreteBuilder BuildPart() : void GetResult() : Product Product For all objects in builder { builder->BuildPart(); } For all objects in builder { builder->BuildPart(); } builder Director: determines how it’s built Constructor takes a builder object Creates an object through the builder’s interface

13. Determine which Concrete Builder you need Create a Director, passing the Builder into it’s constructor Director call build methods in Builder Retrieve the built Product from the Builder

14. Waiter Waiter(PizzaBuilder) GetPizza() : Pizza ConstructPizza() : void PizzaBuilder GetPizza() : Pizza BuildDough() : void BuildSauce() : void BuildToppings() : void HawaiianPizzaBuilder BuildDough() : void BuildSauce() : void BuildToppings() : void SpicyPizzaBuilder BuildDough() : void BuildSauce() : void BuildToppings() : void Pizza SetDough(String) : void SetSauce(String) : void SetToppings(String) : void

15. /** "Product" */ class Pizza { private String dough = ""; private String sauce = ""; private String topping = ""; public void setDough (String dough) { this.dough = dough; } public void setSauce (String sauce) { this.sauce = sauce; } public void setTopping (String topping) { this.topping = topping; } }

16. /** "Abstract Builder" */ abstract class PizzaBuilder { protected Pizza pizza; public void PizzaBuilder() { pizza = new Pizza(); } public Pizza getPizza() { return pizza; } public abstract void buildDough(); public abstract void buildSauce(); public abstract void buildTopping(); }

17. /** "ConcreteBuilder" */ class HawaiianPizzaBuilder extends PizzaBuilder { public void buildDough() { pizza.setDough("cross"); } public void buildSauce() { pizza.setSauce("mild"); } public void buildTopping() { pizza.setTopping("ham+pineapple"); } } /** "ConcreteBuilder" */ class SpicyPizzaBuilder extends PizzaBuilder { public void buildDough() { pizza.setDough("pan baked"); } public void buildSauce() { pizza.setSauce("hot"); } public void buildTopping() { pizza.setTopping("pepperoni+salami"); } }

18. /** "Director" */ class Waiter { private PizzaBuilder pizzaBuilder; public Waiter(PizzaBuilder pb) { pizzaBuilder = pb; } public Pizza getPizza() { return pizzaBuilder.getPizza(); } public void constructPizza() { pizzaBuilder.buildDough(); pizzaBuilder.buildSauce(); pizzaBuilder.buildTopping(); }

19. /** A customer ordering a pizza. */ class BuilderExample { public static void main(String[] args) { // ConcreteBuilder cast as a Builder PizzaBuilder hawaiian= new HawaiianPizzaBuilder(); // Director Waiter waiter = new Waiter(hawaiian); waiter.constructPizza(); // Product Pizza pizza = waiter.getPizza(); }

20.  Concrete Builders create families of objects, like an Abstract Factory  Abstract Factory returns the family of related objects  Builders construct a complex object one step at a time

21. Allows variation from internal object representation and constructed forms Separates code from the construction process Gives finer control over the construction process