package headfirst.combining.observer;public class DuckSimulator {	public static void main(String[] args) {		DuckSimulator simulator = new DuckSimulator();		AbstractDuckFactory duckFactory = new CountingDuckFactory(); 		simulator.simulate(duckFactory);	}  	void simulate(AbstractDuckFactory duckFactory) {  		Quackable redheadDuck = duckFactory.createRedheadDuck();		Quackable duckCall = duckFactory.createDuckCall();		Quackable rubberDuck = duckFactory.createRubberDuck();		Quackable gooseDuck = new GooseAdapter(new Goose()); 		Flock flockOfDucks = new Flock(); 		flockOfDucks.add(redheadDuck);		flockOfDucks.add(duckCall);		flockOfDucks.add(rubberDuck);		flockOfDucks.add(gooseDuck); 		Flock flockOfMallards = new Flock(); 		Quackable mallardOne = duckFactory.createMallardDuck();		Quackable mallardTwo = duckFactory.createMallardDuck();		Quackable mallardThree = duckFactory.createMallardDuck();		Quackable mallardFour = duckFactory.createMallardDuck();		flockOfMallards.add(mallardOne);		flockOfMallards.add(mallardTwo);		flockOfMallards.add(mallardThree);		flockOfMallards.add(mallardFour);		flockOfDucks.add(flockOfMallards);		System.out.println("\nDuck Simulator: With Observer");		Quackologist quackologist = new Quackologist();		flockOfDucks.registerObserver(quackologist);		simulate(flockOfDucks);		System.out.println("\nThe ducks quacked " + 		                   QuackCounter.getQuacks() + 		                   " times");	} 	void simulate(Quackable duck) {		duck.quack();	}}