import java.util.*;
// a - introduce <T extends Goods>, and <T> and T all over.
// I did not need to change anything in the body of any
// of the methods.


public class Store<T extends Goods>{
	private List<T> goods;

	public Store()
	{
		goods = new ArrayList<T>();
	}

	public void add(T good){
	    goods.add(good);
	}
	
	public T remove(){
	    return goods.remove(goods.size()-1);
	}
	
	// 3.c
	// The things we want to add to the store are
	// all subclasses of T. But we need to use
	// the wildcard to be able to pass a collection
	// as parameter. This is ok, since we just want
	// to read the elements from the collection,
	// not to change the collection
	public void addAll(Collection<? extends T> c){
	    for(T elm:c) goods.add(elm);
	   }
	   
	// 3.d
	// Here we need a collection which we can copy
	// all our elements into. Any collection which 
	// can contain our type T - or something more
	// general - can contain our stuff.
	public void sellAll(Collection<? super T> buyer){
	    for(T elm:goods) buyer.add(elm);
	   }
	
}