builder.go

package builder

/*
	separate the construction of a complex object from representation
	设计思想：
		*Builder interface (包含1.biuld_XX method 返回的是biulder接口，2.get_XX 返回对象)
		*父struct
		*Director struct, 属性为Builder, 实现Construct()和SetBuilder()方法
		*不同的子struct组合，实现接口builder
*/
type Wheel int
//定义父struct
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
}

//实现继承Builder
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
}