추상 팩토리 패턴

추상 팩토리 패턴(Abstract factory pattern)은 다양한 구성 요소 별로 '객체의 집합'을 생성해야 할 때 유용하다. 이 패턴을 사용하여 상황에 알맞은 객체를 생성할 수 있다.

대표적인 예로, 자바 프로그래밍 언어의 GUI 구성 요소인 AWT/Swing 라이브러리의 룩 앤드 필 변경 기능을 들 수 있다. 메탈, 마이크로소프트 윈도우, 맥 OS 등의 모양으로 변경할 수 있다. 이에 따라 추상 팩토리에 있는 기본 팩토리 객체가 변경된다. 그러면 이후로 생성되는 GUI 객체들은 전부 해당 룩앤필에 따른다.

구조

UML 클래스 및 시퀀스 다이어그램

클래스 다이어그램

UML 클래스 다이어그램

Lepus3 차트 (범례)

C # 예제

interface IButton
{
    void Paint();
}

interface IGUIFactory
{
    IButton CreateButton();
}

class WinFactory : IGUIFactory
{
    public IButton CreateButton()
    {
        return new WinButton();
    }
}

class OSXFactory : IGUIFactory
{
    public IButton CreateButton()
    {
        return new OSXButton();
    }
}

class WinButton : IButton
{
    public void Paint()
    {
        //Render a button in a Windows style
    }
}

class OSXButton : IButton
{
    public void Paint()
    {
        //Render a button in a Mac OS X style
    }
}

class Program
{
    static void Main()
    {
        var appearance = Settings.Appearance;

        IGUIFactory factory;
        switch (appearance)
        {
            case Appearance.Win:
                factory = new WinFactory();
                break;
            case Appearance.OSX:
                factory = new OSXFactory();
                break;
            default:
                throw new System.NotImplementedException();
        }

        var button = factory.CreateButton();
        button.Paint();
    }
}

Golang 예제

package main

import (
	"fmt"
)

type Button interface {
	Paint()
}

type GUIFactory interface {
	CreateButton() Button
}

type WinFactory struct{}

func (f *WinFactory) CreateButton() Button {
	return new(WinButton)
}

type OSXFactory struct{}

func (f *OSXFactory) CreateButton() Button {
	return new(OSXButton)
}

type LinuxFactory struct{}

func (f *LinuxFactory) CreateButton() Button {
	return new(LinuxButton)
}

type WinButton struct{}

func (b *WinButton) Paint() {
	fmt.Println("WinButton")
}

type OSXButton struct{}

func (b *OSXButton) Paint() {
	fmt.Println("OSXButton")
}

type LinuxButton struct{}

func (b *LinuxButton) Paint() {
	fmt.Println("LinuxButton")
}

func BuildFactory(appearance string) GUIFactory {
	switch appearance {
	case "Window":
		return new(WinFactory)
	case "OSX":
		return new(OSXFactory)
	case "Linux":
		return new(LinuxFactory)
	}
	return nil
}

func main() {
	if factory := BuildFactory("Window"); factory != nil {
		winButton := factory.CreateButton()
		winButton.Paint()
	}

	if factory := BuildFactory("OSX"); factory != nil {
		osxButton := factory.CreateButton()
		osxButton.Paint()
	}

	if factory := BuildFactory("Linux"); factory != nil {
		linuxButton := factory.CreateButton()
		linuxButton.Paint()
	}
}

Python 예제

import enum
from abc import *

class Button:
    @abstractmethod
    def Paint(self):
        pass

class MousePointer:
    @abstractmethod
    def Paint(self):
        pass

class GUIFactory:
    @abstractmethod
    def CreateButton(self):
        return Button

    @abstractmethod
    def CreateMousePointer(self):
        return MousePointer

class WinFactory(GUIFactory):
    def CreateButton(self):
        return WinButton()
    def CreateMousePointer(self):
        return WinMousePointer()

class OSXFactory(GUIFactory):
    def CreateButton(self):
        return OSXButton()
    def CreateMousePointer(self):
        return OSXMousePointer()

class WinMousePointer(MousePointer):
    def Paint(self):
        print("Render a mousepointer in a Windows style")

class OSXMousePointer(MousePointer):
    def Paint(self):
        print ("Render a mousepointer in a OSX style")

class WinButton(Button):
    def Paint(self):
        print ("Render a button in a Windows style")

class OSXButton(Button):
    def Paint(self):
        print ("Render a button in a Mac OSX style")

class Settings:
    @staticmethod
    def Default():
        return Appearance.WIN

class Appearance(enum.Enum):
    WIN = 0
    OSX = 1

def main():
    apperance = Settings.Default()
    if apperance == Appearance.WIN:
        factory = WinFactory()
    elif apperance == Appearance.OSX:
        factory = OSXFactory()
    button = factory.CreateButton()
    mousePointer = factory.CreateMousePointer()
    button.Paint()
    mousePointer.Paint()

if __name__ == '__main__':
    main()

PHP 예제

interface Button
{
    public function paint();
}

interface GUIFactory
{
    public function createButton(): Button;
}

class WinFactory implements GUIFactory
{
    public function createButton(): Button
    {
        return new WinButton();
    }
}

class OSXFactory implements GUIFactory
{
    public function createButton(): Button
    {
        return new OSXButton();
    }
}

class WinButton implements Button
{
    public function paint()
    {
        echo "Windows Button";
    }
}

class OSXButton implements Button
{
    public function paint()
    {
        echo "OSX Button";
    }
}

$appearance = "osx";

$factory = NULL;

switch ($appearance) {
    case "win":
        $factory = new WinFactory();
        break;
    case "osx":
        $factory = new OSXFactory();
        break;
    default:
        break;
}

if ($factory instanceof GUIFactory) {
    $button = $factory->createButton();
    $button->paint();
}