Paradigmas de Linguagens de Programacao Aula #7 Prof. Ismar Frango

1. Paradigmas de Linguagens de Programação Paradigma Orientado a Objetos Aula #7 (CopyLeft)2009 - Ismar Frango ismar@mackenzie.br

2. “ There are only two kinds of languages: the ones people complain about and the ones nobody uses.” Bjarne Stroustrup Binding em LOO

5. 22/09/09

7. invariância covariância contravariância   

10. 22/09/09 ?

11. ?

12. Asteroid SpaceShip Thing Dispatching em LOO

13. abstract class Thing { public abstract void collideWith ( Thing other); } class Asteroid extends Thing { public void collideWith ( Thing other) { if (other instanceof Asteroid ) { // handle Asteroid-Asteroid collision } else if (other instanceof Spaceship ) { // handle Asteroid-Spaceship collision } } } class Spaceship extends Thing { public void collideWith ( Thing other) { if (other instanceof Asteroid ) { // handle Spaceship-Asteroid collision } else if (other instanceof Spaceship ) { // handle Spaceship-Spaceship collision } } }

14. abstract class Thing { public abstract void collideWith ( Thing other); } class Asteroid extends Thing { public void collideWith ( Asteroid other) { System.out.println("handle Asteroid-Asteroid collision"); } public void collideWith ( Spaceship s) { System.out.println("handle Asteroid-Spaceship collision"); } } class Spaceship extends Thing { public void collideWith ( Asteroid a) { System.out.println("handle Spaceship-Asteroid collision"); } public void collideWith ( Spaceship other) { System.out.println("handle Spaceship-Spaceship collision"); } } 

15. abstract class Thing { public abstract void collideWith ( Thing other); } class Asteroid extends Thing { public void collideWith ( Thing other) {} public void collideWith ( Asteroid other) { System.out.println("handle Asteroid-Asteroid collision"); } public void collideWith ( Spaceship s) { System.out.println("handle Asteroid-Spaceship collision"); } } class Spaceship extends Thing { public void collideWith ( Thing other) {} public void collideWith ( Asteroid a) { System.out.println("handle Spaceship-Asteroid collision"); } public void collideWith ( Spaceship other) { System.out.println("handle Spaceship-Spaceship collision"); } } 

16. Asteroid ExplodingAsteroid SpaceShip GiantSpaceShip Thing

17. class SpaceShip {}; class GiantSpaceShip : public SpaceShip {}; class Asteroid { public : virtual void CollideWith (SpaceShip&) { cout << &quot;Asteroid hit a SpaceShip&quot; << endl; } virtual void CollideWith (GiantSpaceShip&) { cout << &quot;Asteroid hit a GiantSpaceShip&quot; << endl; } }; class ExplodingAsteroid : public Asteroid { public : virtual void CollideWith (SpaceShip&) { cout << &quot;ExplodingAsteroid hit a SpaceShip&quot; << endl; } virtual void CollideWith (GiantSpaceShip&) { cout << &quot;ExplodingAsteroid hit a GiantSpaceShip&quot; << endl; } };

18. class SpaceShip {}; class GiantSpaceShip : public SpaceShip {}; class Asteroid { public : virtual void CollideWith (SpaceShip&) { cout << &quot;Asteroid hit a SpaceShip&quot; << endl; } virtual void CollideWith (GiantSpaceShip&) { cout << &quot;Asteroid hit a GiantSpaceShip&quot; << endl; } }; class ExplodingAsteroid : public Asteroid { public : virtual void CollideWith (SpaceShip&) { cout << &quot;ExplodingAsteroid hit a SpaceShip&quot; << endl; } virtual void CollideWith (GiantSpaceShip&) { cout << &quot;ExplodingAsteroid hit a GiantSpaceShip&quot; << endl; } }; Asteroid theAsteroid; SpaceShip theSpaceShip; GiantSpaceShip theGiantSpaceShip; theAsteroid . CollideWith (theSpaceShip); theAsteroid . CollideWith (theGiantSpaceShip); Asteroid * theAsteroidReference = new ExplodingAsteroid (); theAsteroidReference -> CollideWith (theSpaceShip); theAsteroidReference -> CollideWith (theGiantSpaceShip); SpaceShip & theSpaceShipReference = theGiantSpaceShip; theAsteroid . CollideWith (theSpaceShipReference); theAsteroidReference -> CollideWith (theSpaceShipReference);

19. class SpaceShip { virtual void CollideWith ( Asteroid & inAsteroid) { inAsteroid. CollideWith (* this ); } }; class GiantSpaceShip : public SpaceShip {}; Asteroid hit a SpaceShip ExplodingAsteroid hit a SpaceShip SpaceShip & theSpaceShipReference = theGiantSpaceShip; Asteroid & theAsteroidReference = theExplodingAsteroid; theSpaceShipReference. CollideWith (theAsteroid); theSpaceShipReference. CollideWith (theAsteroidReference); class SpaceShip { virtual void CollideWith ( Asteroid & inAsteroid) { inAsteroid. CollideWith (* this ); } }; class GiantSpaceShip : public SpaceShip { virtual void CollideWith ( Asteroid & inAsteroid) { inAsteroid. CollideWith (* this ); } }; Asteroid hit a GiantSpaceShip ExplodingAsteroid hit a GiantSpaceShip

20. O Padrão Visitor