By James Sheets

An object creational pattern.

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

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

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.

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Director

Constructor()

Builder

BuildPart() : void

ConcreteBuilder

BuildPart() : void

GetResult() : Product

ProductFor all objects in builder { builder->BuildPart();}

For all objects in builder { builder->BuildPart();}

builder

Waiter

Waiter(PizzaBuilder)GetPizza() : PizzaConstructPizza() : void

PizzaBuilder

GetPizza() : PizzaBuildDough() : voidBuildSauce() : voidBuildToppings() : void

HawaiianPizzaBuilder

BuildDough() : voidBuildSauce() : voidBuildToppings() : void

SpicyPizzaBuilder

BuildDough() : voidBuildSauce() : voidBuildToppings() : void

Pizza

SetDough(String) : voidSetSauce(String) : voidSetToppings(String) : void

/** "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; }

}

/** "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();

}

/** "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"); }

}

/** "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();

} }

/** A customer ordering a pizza. */ class BuilderExample {

public static void main(String[] args) {

// ConcreteBuilder cast as a BuilderPizzaBuilder hawaiian= new HawaiianPizzaBuilder(); // DirectorWaiter waiter = new Waiter(hawaiian);

waiter.constructPizza(); // ProductPizza pizza = waiter.getPizza();

} }

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