서로 관련있는 여러 객체를 만들어주는 인터페이스.

• 구체적으로 어떤 클래스의 인스턴스를 사용하는지 감출 수 있다.

추상 팩토리 패턴 구현 방법

• 클라이언트 코드에서 구체적인 클래스의 의존성을 제거한다.

1. Simple factory

• 객체를 생성하는 클래스를 따로 두는 것

public interface Phone {
    void complete();
}

public class ApplePhone implements Phone {
    @Override
    public void complete() {
        System.out.println("apple phone complete");
    }
}

public class SamsungPhone implements Phone {
    @Override
    public void complete() {
        System.out.println("samsung phone complete");
    }
}

public class SimplePhoneFactory {
    public Phone orderPhone(String type) {
        Phone phone = createPhone(type);
        phone.complete();
        return phone;
    }

    private Phone createPhone(String type) {
        Phone phone;
        switch (type){
            case "APPLE":
                phone = new ApplePhone();
                break;
            case "SAMSUNG":
                phone = new SamsungPhone();
                break;
            default:
                throw new IllegalArgumentException("Illegal type");
        }
        return phone;
    }
}

public class Client {
    public static void main(String[] args) {
        SimplePhoneFactory simplePhoneFactory = new SimplePhoneFactory();
        Phone apple = simplePhoneFactory.orderPhone("APPLE");
        Phone samsung = simplePhoneFactory.orderPhone("SAMSUNG");
    }
}

1. Factory method

• 클래스의 인스턴스 만드는 일을 서브 클래스에게 맡기는 것

public interface Phone {
    void complete();
}

public class ApplePhone implements Phone {
    @Override
    public void complete() {
        System.out.println("apple phone complete");
    }
}

public class SamsungPhone implements Phone {
    @Override
    public void complete() {
        System.out.println("samsung phone complete");
    }
}

public interface PhoneFactory {
    default Phone orderPhone() {
        Phone phone = createPhone();
        phone.complete();
        return phone;
    }

    Phone createPhone();
}

public class AppleFactory implements PhoneFactory {
    @Override
    public Phone createPhone() {
        return new ApplePhone();
    }
}

public class SamsungFactory implements PhoneFactory {
    @Override
    public Phone createPhone() {
        return new SamsungPhone();
    }
}

public class Client {
    public static void main(String[] args) {
        PhoneFactory appleFactory = new AppleFactory();
        Phone applePhone = appleFactory.orderPhone();

        PhoneFactory samsungFactory = new SamsungFactory();
        Phone samsungPhone = samsungFactory.orderPhone();
    }
}