Golang设计模式（工厂方法模式）

工厂方法模式类图，

image.png

abstract_factory_test.go

// abstract_factory_test
package abstract_factory

import (
    "testing"
)

func TestMotorbikeFactory(t *testing.T) {
    motobikeF, err := GetVehicleFactory(MotobikeFactoryType)
    if err != nil {
        t.Fatal("Create motorbike vehicle factory failed")
    }

    vehicle, err := motobikeF.GetVehicle(SportMotorbikeType)
    if err != nil {
        t.Fatal("Create sports motor bike failed")
    }

    sportVehicle, ok := vehicle.(Motorbike)

    if !ok {
        t.Fatal("vehicle is not a motorbike")
    }

    t.Logf("Motorbike type is %d", sportVehicle.GetType())

    _, err = motobikeF.GetVehicle(3)
    if err == nil {
        t.Fatalf("There is no motor bike type is %d", 3)
    }

}

car_factory.go

// car_factory
package abstract_factory

import (
    "errors"
    "fmt"
)

const (
    LuxuryCarType   = 1
    FamiliarCarType = 2
)

type CarFactory struct{}

func (c *CarFactory) GetVehicle(v int) (Vehicle, error) {
    switch v {
    case LuxuryCarType:
        return new(LuxuryCar), nil
    case FamiliarCarType:
        return new(FamiliarCar), nil
    default:
        return nil, errors.New(fmt.Sprintf("Car of type %v not recognized", v))
    }
}

motorbike_factory.go

// motorbike_factory
package abstract_factory

import (
    "errors"
    "fmt"
)

const (
    SportMotorbikeType  = 1
    CruiseMotorbikeType = 2
)

type MotobikeFactory struct{}

func (m *MotobikeFactory) GetVehicle(v int) (Vehicle, error) {
    switch v {
    case SportMotorbikeType:
        return new(SportMotorbike), nil
    case CruiseMotorbikeType:
        return new(CruiseMotorbike), nil
    default:
        return nil, errors.New(fmt.Sprintf("type of motorbike %v not recognized", v))
    }
}

vehicle.go

// vehicle
package abstract_factory

type Vehicle interface {
    GetWheels() int
    GetSeats() int
}

car.go

// car
package abstract_factory

type Car interface {
    GetDoors() int
}

motorbike.go

// motorbike
package abstract_factory

type Motorbike interface {
    GetType() int
}

luxury_car.go

// luxury_car
package abstract_factory

type LuxuryCar struct{}

func (l *LuxuryCar) GetDoors() int {
    return 4
}

func (l *LuxuryCar) GetWheels() int {
    return 4
}

func (l *LuxuryCar) GetSeats() int {
    return 5
}

familiar_car.go

// familiar_car
package abstract_factory

type FamiliarCar struct{}

func (f *FamiliarCar) GetDoors() int {
    return 5
}

func (f *FamiliarCar) GetWheels() int {
    return 4
}

func (f *FamiliarCar) GetSeats() int {
    return 5
}

sport_motorbike.go

// sport_motorbike
package abstract_factory

type SportMotorbike struct{}

func (s *SportMotorbike) GetType() int {
    return SportMotorbikeType
}

func (s *SportMotorbike) GetWheels() int {
    return 2
}
func (s *SportMotorbike) GetSeats() int {
    return 2
}

cruise_motorbike.go

// cruise_motorbike
package abstract_factory

type CruiseMotorbike struct{}

func (c *CruiseMotorbike) GetType() int {
    return CruiseMotorbikeType
}

func (c *CruiseMotorbike) GetWheels() int {
    return 2
}
func (c *CruiseMotorbike) GetSeats() int {
    return 2
}

程序输出如下，单元测试不太充分，不想写了。覆盖率才到25%。

image.png