Паттерн Фабричный Метод, как все остальные разновидности фабрик, предоставляет интерфейс к методу создания объектов, также называемому "фабричным методом". Остальные методы, реализуемые в абстрактном классе Creator, работают с продуктами, созданными фабричным методом. Только субклассы фактически реализуют фабричный метод и создают продукты.
Рассмотрим паттерн на примере заказа пиццы с использованием фабричного метода.
/* Product - Pizza */
var Pizza = function () {
this.prepare = function () {
console.log("Preparing " + this.name);
console.log("Tossing dough...");
console.log("Adding sauce...");
console.log("Adding toppings: ");
for (var i = 0; i < this.toppings.length; i++) {
console.log(" " + this.toppings[i]);
}
};
this.bake = function () {
console.log("Bake for 25 minutes at 350");
};
this.cut = function () {
console.log("Cutting the pizza into diagonal slices");
};
this.box = function () {
console.log("Place pizza in official PizzaStore box");
};
this.getName = function () {
return this.name;
};
};
/* ConcreteProduct - NYStyleCheesePizza */
var NYStyleCheesePizza = function () {
this.name = "NY Style Sauce and Cheese Pizza";
this.dough = "Thin Crust Dough";
this.sauce = "Marinara Sauce";
this.toppings = ["Grated Reggiano Cheese"];
};
NYStyleCheesePizza.prototype = new Pizza();
NYStyleCheesePizza.prototype.constructor = NYStyleCheesePizza;
/* ConcreteProduct - ChicagoStyleCheesePizza */
var ChicagoStyleCheesePizza = function () {
this.name = "Chicago Style Deep Dish Cheese Pizza";
this.dough = "Extra Thick Crust Dough";
this.sauce = "Plum Tomato Sauce";
this.toppings = ["Shredded Mozzarella Cheese"];
this.cut = function () {
console.log("Cutting the pizza into square slices");
};
};
ChicagoStyleCheesePizza.prototype = new Pizza();
ChicagoStyleCheesePizza.prototype.constructor = ChicagoStyleCheesePizza;
/* Creator - PizzaStore */
var PizzaStore = function () {
this.orderPizza = function () {
var pizza = this.createPizza();
pizza.prepare();
pizza.bake();
pizza.cut();
pizza.box();
return pizza
};
// abstract createPizza();
};
/* ConcreteCreator - NYPizzaStore */
var NYPizzaStore = function () {
// factory method
this.createPizza = function () {
return new NYStyleCheesePizza();
};
};
NYPizzaStore.prototype = new PizzaStore();
NYPizzaStore.prototype.constructor = NYPizzaStore;
/* ConcreteCreator - NYPizzaStore */
var ChicagoPizzaStore = function () {
// factory method
this.createPizza = function () {
return new ChicagoStyleCheesePizza();
};
};
ChicagoPizzaStore.prototype = new PizzaStore();
ChicagoPizzaStore.prototype.constructor = ChicagoPizzaStore;
/* test application */
var Application = function () {
this.run = function () {
var nyStore = new NYPizzaStore();
var chicagoStore = new ChicagoPizzaStore();
var pizza = nyStore.orderPizza();
console.log("Ethan ordered a " + pizza.getName());
pizza = chicagoStore.orderPizza();
console.log("Joel ordered a " + pizza.getName());
};
};
var application = new Application();
application.run();
На выходе:
Preparing NY Style Sauce and Cheese Pizza
Tossing dough...
Adding sauce...
Adding toppings:
Grated Reggiano Cheese
Bake for 25 minutes at 350
Cutting the pizza into diagonal slices
Place pizza in official PizzaStore box
Ethan ordered a NY Style Sauce and Cheese Pizza
Preparing Chicago Style Deep Dish Cheese Pizza
Tossing dough...
Adding sauce...
Adding toppings:
Shredded Mozzarella Cheese
Bake for 25 minutes at 350
Cutting the pizza into square slices
Place pizza in official PizzaStore box
Joel ordered a Chicago Style Deep Dish Cheese Pizza