WhoNeedsVisitor

WhoNeedsVisitor.groovy

SpaceShip ship = new BigSpaceShip();
LauncherSystem launcher = new LauncherSystem();

launcher.launch(ship);				

class LauncherSystem{
	public void launch(SpaceShip ship){
		Launcher launcher = new Launcher();
		launcher.launch(ship);
	}
}

class Launcher{
	public void launch(SpaceShip ship){
		System.out.println("Got a SpaceShip");			
	}
	public void launch(BigSpaceShip ship){
		System.out.println("Got a BigSpaceShip");			
	}
}

class BigSpaceShip extends SpaceShip{
}
class SpaceShip{
}