Строител (шаблон)

Строител (Builder) е създаващ шаблон за дизайн, който се използва в обектно-ориентираното програмиране.

Целта е да се раздели създаването на сложен обект от неговото представяне (интерфейс), за да може с един и същ процес да се създават обекти с различно представяне.

UML диаграма на шаблона Строител

Примери

C++

// Реализация на C++.
 
#include <iostream>
#include <memory>
#include <string>
 
// Product
class Pizza
{
private:
    std::string dough;
    std::string sauce;
    std::string topping;
 
public:
    Pizza() { }
    ~Pizza() { }
 
    void SetDough(const std::string& d) { dough = d; };
    void SetSauce(const std::string& s) { sauce = s; };
    void SetTopping(const std::string& t) { topping = t; }
 
    void ShowPizza()
    {
        std::cout << " Yummy !!!" << std::endl
        << "Pizza with Dough as " << dough
        << ", Sauce as " << sauce
        << " and Topping as " << topping
        << " !!! " << std::endl;
    }
};
 
// Abstract Builder
class PizzaBuilder
{
protected:
    std::auto_ptr<Pizza> pizza;
public:
    PizzaBuilder() {}
    virtual ~PizzaBuilder() {}
    std::auto_ptr<Pizza> GetPizza() { return pizza; }
 
    void createNewPizzaProduct() { pizza.reset (new Pizza); }
 
    virtual void buildDough()=0;
    virtual void buildSauce()=0;
    virtual void buildTopping()=0;
 
};
 
// ConcreteBuilder
class HawaiianPizzaBuilder : public PizzaBuilder
{
public:
    HawaiianPizzaBuilder() : PizzaBuilder() {}
    ~HawaiianPizzaBuilder(){}
 
    void buildDough() { pizza->SetDough("cross"); }
    void buildSauce() { pizza->SetSauce("mild"); }
    void buildTopping() { pizza->SetTopping("ham and pineapple"); }
};
 
// ConcreteBuilder
class SpicyPizzaBuilder : public PizzaBuilder
{
public:
    SpicyPizzaBuilder() : PizzaBuilder() {}
    ~SpicyPizzaBuilder() {}
 
    void buildDough() { pizza->SetDough("pan baked"); }
    void buildSauce() { pizza->SetSauce("hot"); }
    void buildTopping() { pizza->SetTopping("pepperoni and salami"); }
};
 
// Director
class Waiter
{
private:
    PizzaBuilder* pizzaBuilder;
public:
    Waiter() : pizzaBuilder(NULL) {}
    ~Waiter() { }
 
    void SetPizzaBuilder(PizzaBuilder* b) { pizzaBuilder = b; }
    std::auto_ptr<Pizza> GetPizza() { return pizzaBuilder->GetPizza(); }
    void ConstructPizza()
    {
        pizzaBuilder->createNewPizzaProduct();
        pizzaBuilder->buildDough();
        pizzaBuilder->buildSauce();
        pizzaBuilder->buildTopping();
    }
};
 
// Клиент поръчва 2 пици
int main()
{ 
    Waiter waiter;
 
    HawaiianPizzaBuilder hawaiianPizzaBuilder;
    waiter.SetPizzaBuilder (&hawaiianPizzaBuilder);
    waiter.ConstructPizza();
    std::auto_ptr<Pizza> pizza = waiter.GetPizza();
    pizza->ShowPizza();
 
    SpicyPizzaBuilder spicyPizzaBuilder;
    waiter.SetPizzaBuilder(&spicyPizzaBuilder);
    waiter.ConstructPizza();
    pizza = waiter.GetPizza();
    pizza->ShowPizza();
 
    return EXIT_SUCCESS;
}

C#

 using System;
 using System.Collections;
 
 namespace Builder
 {
 
  public class MainApp
  {
    public static void Main()
    {
      // Create director and builders
      Director director = new Director();
 
      Builder b1 = new ConcreteBuilder1();
      Builder b2 = new ConcreteBuilder2();
 
      // Construct two products
      director.Construct(b1);
      Product p1 = b1.GetResult();
      p1.Show();
 
      director.Construct(b2);
      Product p2 = b2.GetResult();
      p2.Show();
 
      // Wait for user
      Console.Read();
    }
  }
 
  // "Director"
 
  class Director
  {
    // Builder uses a complex series of steps
    public void Construct(Builder builder)
    {
      builder.BuildPartA();
      builder.BuildPartB();
    }
  }
 
  // "Builder"
 
  abstract class Builder
  {
    public abstract void BuildPartA();
    public abstract void BuildPartB();
    public abstract Product GetResult();
  }
 
  // "ConcreteBuilder1"
 
  class ConcreteBuilder1 : Builder
  {
    private readonly Product product = new Product();
 
    public override void BuildPartA()
    {
      product.Add("PartA");
    }
 
    public override void BuildPartB()
    {
      product.Add("PartB");
    }
 
    public override Product GetResult()
    {
      return product;
    }
  }
 
  // "ConcreteBuilder2"
 
  class ConcreteBuilder2 : Builder
  {
    private readonly Product product = new Product();
 
    public override void BuildPartA()
    {
      product.Add("PartX");
    }
 
    public override void BuildPartB()
    {
      product.Add("PartY");
    }
 
    public override Product GetResult()
    {
      return product;
    }
  }
 
  // "Product"
 
  class Product
  {
    private readonly ArrayList parts = new ArrayList();
 
    public void Add(string part)
    {
      parts.Add(part);
    }
 
    public void Show()
    {
      Console.WriteLine("\nProduct Parts -------");
      foreach (string part in parts)
        Console.WriteLine(part);
    }
  }
 }

Java

 /** "Product" */
 class Pizza {
    private String dough = "";
    private String sauce = "";
    private String topping = "";
 
    public void setDough(String dough)     { this.dough = dough; }
    public void setSauce(String sauce)     { this.sauce = sauce; }
    public void setTopping(String topping) { this.topping = topping; }
 }
 
 
 /** "Abstract Builder" */
 abstract class PizzaBuilder {
    protected Pizza pizza;
 
    public Pizza getPizza() { return pizza; }
    public void createNewPizzaProduct() { pizza = new Pizza(); }
 
    public abstract void buildDough();
    public abstract void buildSauce();
    public abstract void buildTopping();
 }
 
 /** "ConcreteBuilder" */
 class HawaiianPizzaBuilder extends PizzaBuilder {
    public void buildDough()   { pizza.setDough("cross"); }
    public void buildSauce()   { pizza.setSauce("mild"); }
    public void buildTopping() { pizza.setTopping("ham+pineapple"); }
 }
 
 /** "ConcreteBuilder" */
 class SpicyPizzaBuilder extends PizzaBuilder {
    public void buildDough()   { pizza.setDough("pan baked"); }
    public void buildSauce()   { pizza.setSauce("hot"); }
    public void buildTopping() { pizza.setTopping("pepperoni+salami"); }
 }
 
 
 /** "Director" */
 class Waiter {
    private PizzaBuilder pizzaBuilder;
 
    public void setPizzaBuilder(PizzaBuilder pb) { pizzaBuilder = pb; }
    public Pizza getPizza() { return pizzaBuilder.getPizza(); }
 
    public void constructPizza() {
       pizzaBuilder.createNewPizzaProduct();
       pizzaBuilder.buildDough();
       pizzaBuilder.buildSauce();
       pizzaBuilder.buildTopping();
    }
 }
 
 
 /** Клиент поръчва пица. */
 class BuilderExample {
    public static void main(String[] args) {
        Waiter waiter = new Waiter();
        PizzaBuilder hawaiian_pizzabuilder = new HawaiianPizzaBuilder();
        PizzaBuilder spicy_pizzabuilder = new SpicyPizzaBuilder();
 
        waiter.setPizzaBuilder( hawaiian_pizzabuilder );
        waiter.constructPizza();
 
        Pizza pizza = waiter.getPizza();
    }
 }

PHP

/* Produit */
class Pizza {
  private $_pate = "";
  private $_sauce = "";
  private $_garniture = "";
 
  public function setPate($pate)           { $this->_pate = $pate; }
  public function setSauce($sauce)         { $this->_sauce = $sauce; }
  public function setGarniture($garniture) { $this->_garniture = $garniture; }
}
 
 
/* Monteur */
abstract class MonteurPizza {
  protected $_pizza;
 
  public function getPizza()           { return $this->_pizza; }
  public function creerNouvellePizza() { $this->_pizza = new Pizza(); }
 
  abstract public function monterPate();
  abstract public function monterSauce();
  abstract public function monterGarniture();
}
 
/* MonteurConcret */
class MonteurPizzaHawaii extends MonteurPizza {
  public function monterPate()      { $this->_pizza.setPate("croisée"); }
  public function monterSauce()     { $this->_pizza.setSauce("douce"); }
  public function monterGarniture() { $this->_pizza.setGarniture("jambon+ananas"); }
}
 
/* MonteurConcret */
class MonteurPizzaPiquante extends MonteurPizza {
  public function monterPate()      { $this->_pizza.setPate("feuilletée"); }
  public function monterSauce()     { $this->_pizza.setSauce("piquante"); }
  public function monterGarniture() { $this->_pizza.setGarniture("pepperoni+salami"); }
}
 
 
/* Directeur */
class Serveur {
  private $_monteurPizza;
 
  public function setMonteurPizza(MonteurPizza $mp) { $this->_monteurPizza = $mp; }
  public function getPizza()                        { return $this->_monteurPizza->getPizza(); }
 
  public void construirePizza() {
    $this->_monteurPizza->creerNouvellePizza();
    $this->_monteurPizza->monterPate();
    $this->_monteurPizza->monterSauce();
    $this->_monteurPizza->monterGarniture();
  }
}
 
/* Клиент поръчва пица. */
$serveur = new Serveur();
$monteurPizzaHawaii  = new MonteurPizzaHawaii();
$monteurPizzaPiquante = new MonteurPizzaPiquante();
 
$serveur->setMonteurPizza($monteurPizzaHawaii);
$serveur->construirePizza();
 
$pizza = $serveur->getPizza();