Factory Pattern

Definition

"Define an interface for creating an object, but let the classes that implement the interface decide which class to instantiate. The Factory method lets a class defer instantiation to subclasses."

Example

public class MazeGame {
  public MazeGame() {
     Room room1 = makeRoom();
     Room room2 = makeRoom();
     room1.connect(room2);
     this.addRoom(room1);
     this.addRoom(room2);
  }
 
  protected Room makeRoom() {
     return new OrdinaryRoom();
  }
}

public class MagicMazeGame extends MazeGame {
  @Override
  protected Room makeRoom() {
      return new MagicRoom();
  }
}

หรือ

/* factory and car interfaces */
 
interface CarFactory {
    public function makeCar();
}
 
interface Car {
    public function getType();
}
 
/* concrete implementations of the factory and car */ 
 
class SedanFactory implements CarFactory {
    public function makeCar() {
        return new Sedan();
    }
}
 
class Sedan implements Car {
    public function getType() {
        return 'Sedan';
    }
}
 
/* client */
 
$factory = new SedanFactory();
$car = $factory->makeCar();
print $car->getType();

ref : wiki