造者模式Golang

造者模式(Builder Pattern)

将一个复杂对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示。
抽象建造者类中定义了产品的创建方法和返回方法.
建造者模式的结构中还引入了一个指挥者类Director，该类的作用主要有两个：一方面它隔离了客户与生产过程；
另一方面它负责控制产品的生成过程。指挥者针对抽象建造者编程，客户端只需要知道具体建造者的类型，
即可通过指挥者类调用建造者的相关方法，返回一个完整的产品对象.

type Wheel int
type Vehicle struct {
	Wheels	  Wheel
	Seats 	  int
	Structure string
}

//builder interface
type Builder interface {
	SetWheels()		Builder
	SetSeats()		Builder
	SetStructure()  Builder
	GetVehicle()	Vehicle
}

//Director
type Director struct {
	builder Builder
}

func (director *Director) Construct() {
	director.builder.SetWheels().SetSeats().SetStructure()  //链式调用
}

func (director *Director) SetBuilder(builder Builder) {
	director.builder = builder
}

//car struct
type Car struct {
	vehicle Vehicle
}

func (car *Car) SetWheels() Builder {
	car.vehicle.Wheels = 4
	return car
}
func (car *Car) SetSeats() Builder {
	car.vehicle.Seats = 4
	return car
}
func (car *Car) SetStructure() Builder {
	car.vehicle.Structure = "Car"
	return car
}
func (car *Car) GetVehicle() Vehicle {
	return car.vehicle
}