팩토리 메서드 패턴

UML로 표현된 팩토리 메서드

LePUS3로 표현된 펙토리 메서드

팩토리 메서드 패턴(Factory method pattern)은 객체지향 디자인 패턴이다. 다른 생성 패턴들처럼, 이 패턴도 생성하려는 객체의 클래스를 정확히 지정하지 않으면서 객체를 만드는 문제를 다룬다. 팩토리 메서드 패턴은 이 문제를 객체를 만드는 또 다른 메서드를 정의하여 처리한다. 일반적으로, 팩토리 메서드라는 용어는 객체를 만드는 것이 주 목적인 메서드를 지칭하는데 주로 사용한다.

예

C#

Pizza example:

public abstract class Pizza
{
    public abstract decimal GetPrice();
 
    public enum PizzaType
    {
        HamMushroom, Deluxe, Seafood
    }
    public static Pizza PizzaFactory(PizzaType pizzaType)
    {
        switch (pizzaType)
        {
            case PizzaType.HamMushroom:
                return new HamAndMushroomPizza();
 
            case PizzaType.Deluxe:
                return new DeluxePizza();
 
            case PizzaType.Seafood:
                return new SeafoodPizza();
 
        }
 
        throw new System.NotSupportedException("The pizza type " + pizzaType.ToString() + " is not recognized.");
    }
}
public class HamAndMushroomPizza : Pizza
{
    private decimal price = 8.5M;
    public override decimal GetPrice() { return price; }
}
 
public class DeluxePizza : Pizza
{
    private decimal price = 10.5M;
    public override decimal GetPrice() { return price; }
}
 
public class SeafoodPizza : Pizza
{
    private decimal price = 11.5M;
    public override decimal GetPrice() { return price; }
}
 
// Somewhere in the code
...
  Console.WriteLine( Pizza.PizzaFactory(Pizza.PizzaType.Seafood).GetPrice().ToString("C2") ); // $11.50
...

자바스크립트

Pizza example:

//Our pizzas
function HamAndMushroomPizza(){
  var price = 8.50;
  this.getPrice = function(){
    return price;
  }
}
 
function DeluxePizza(){
  var price = 10.50;
  this.getPrice = function(){
    return price;
  }
}
 
function SeafoodPizza(){
  var price = 11.50;
  this.getPrice = function(){
    return price;
  }
}
 
//Pizza Factory
function PizzaFactory(){
  this.createPizza = function(type){
     switch(type){
      case "Ham and Mushroom":
        return new HamAndMushroomPizza();
      case "DeluxePizza":
        return new DeluxePizza();
      case "Seafood Pizza":
        return new SeafoodPizza();
      default:
          return new DeluxePizza();
     }     
  }
}
 
//Usage
var pizzaPrice = new PizzaFactory().createPizza("Ham and Mushroom").getPrice();
alert(pizzaPrice);

루비

Pizza example:

class HamAndMushroomPizza
  def price
    8.50
  end
end
 
class DeluxePizza
  def price
    10.50
  end
end
 
class SeafoodPizza
  def price
    11.50
  end
end
 
class PizzaFactory
  def create_pizza(style='')
    case style
      when 'Ham and Mushroom'
        HamAndMushroomPizza.new
      when 'DeluxePizza'
        DeluxePizza.new
      when 'Seafood Pizza'
        SeafoodPizza.new
      else
        DeluxePizza.new
    end   
  end
end
 
# usage
factory = PizzaFactory.new
pizza = factory.create_pizza('Ham and Mushroom')
pizza.price #=> 8.5
# bonus formatting
formatted_price = sprintf("$%.2f", pizza.price) #=> "$8.50"
# one liner
sprintf("$%.2f", PizzaFactory.new.create_pizza('Ham and Mushroom').price) #=> "$8.50"

파이썬

# Our Pizzas
 
class Pizza:
    HAM_MUSHROOM_PIZZA_TYPE = 0
    DELUXE_PIZZA_TYPE = 1
    SEAFOOD_PIZZA_TYPE= 2
 
    def __init__(self):
        self.__price = None
 
    def getPrice(self):
        return self.__price
 
class HamAndMushroomPizza(Pizza):
    def __init__(self):
        self.__price = 8.50
 
class DeluxePizza(Pizza):
    def __init__(self):
        self.__price = 10.50
 
class SeafoodPizza(Pizza):
    def __init__(self):
        self.__price = 11.50
 
class PizzaFactory:
    def createPizza(self, pizzaType):
        if pizzaType == Pizza.HAM_MUSHROOM_PIZZA_TYPE:
            return HamAndMushroomPizza()
        elif pizzaType == Pizza.DELUXE_PIZZA_TYPE:
            return DeluxePizza()
        elif pizzaype == Pizza.SEAFOOD_PIZZA_TYPE:
            return SeafoodPizza()
        else:
            return DeluxePizza()
 
# Usage
pizzaPrice = PizzaFactory().createPizza(Pizza.HAM_MUSHROOM_PIZZA_TYPE).getPrice()
print "$%.02f" % pizzaPrice