import java.util.*;
public class FoodExample {
	public static void main(String[] args){
		Animal<?> a;
		Omniwore o;
		Tiger t;

		List< Animal<?> > lo = new ArrayList<Animal<?>>();
		//List<Omniwore> lo = new ArrayList<Omniwore>();
		//List<Tiger> lo = new ArrayList<Tiger>();
		t = new Tiger();
		a=t;
		a.feed(new Food());

		lo.add(t);
		lo.get(0).feed(new Meat() );
		//t.feed(new Food()); // compile time error
		t.feed(new Meat());
		//t.feed(new Grass());// compile time error

		// o = t; // compile time error
		o = new Omniwore();
		o.feed(new Food());
		o.feed(new Meat());
		o.feed(new Grass());

		a = o; // OK
		a = (Animal)t; // Warning
		a = (Animal<Meat>)t; // OK
		a = (Animal<?>)t; // compiler time error
		//o = (Omniwore)a; // NOT OK

		//a.feed(new Food()); // compile time error
		//a.feed(new Meat()); // compile time error
		//a.feed(new Grass());// compile time error

	}
}



class Animal<SomeFood>{
	void feed(SomeFood f){
		System.out.println(this.getClass().getName() + " was fed " + f);
	};
}

class Omniwore extends Animal<Food>{};

class Tiger extends Animal<Meat>{};

class Cow extends Animal<Grass>{};

class Food{public String toString(){return "Food";} };

class Grass extends Food{public String toString(){return "Grass";}};

class Meat extends Food{public String toString(){return "Meat";} };