abstract_factory

Creational » Abstract Factory

Elements

• AbstractFactory
• ConcreteFactory
• AbstactProduct
• Product
• Client

Description

The difference from factory design pattern is that with this pattern it is possible to manage complex data type.

Implementation

The better way to explain this pattern is to show its power. We need just three steps. First of all we create a factory of italian cars. Second we can ask to this factory a Ferrari.

func TestFoo(t *testing.T) {
	itaF, _ := BuildFactory(ItalianType)
	m, _ := itaF.Build(FerrariModel)

	car, ok := m.(Vehicle)
	if !ok {
		t.Fatal("Invalid model")
	}

	t.Logf("%v car has %d wheels", car.GetModelName(), car.NumOfWheels())
}

Usage

BuildFactory provide a factory of italian cars. Then italian builder build a particular model of car. This model must have 4 wheels.

fca, _ := BuildFactory(ItalianType)
m, _ := fca.Build(FerrariModel)
car, err := m.(Vehicle)
if model.NumOfWheels() != 4 {
  panic("Ferrari shoud have 4 wheels")
}

BuildFactory provide a factory of italian cars. Then italian builder build a particular model of car. This model must have 5 wheels.

fca, _ := BuildFactory(ItalianType)
model, _ := fca.Build(CarWithFiveWheelModel)
if model.NumOfWheels() != 5 {
  panic("the car should have 5 wheels")
}