import java.util.LinkedList;
import java.util.ListIterator;
import java.util.Random;

/** BagLinkedList.java -- Here is a 2nd implementation of a bag, using
 *  a Java LinkedList for our Items instead of an ArrayList.
 *  We'll use inheritance to save us having to define functions that
 *  already exist exactly how we want.  For example, LinkedList already has
 *  methods for add, remove and size.
 */
public class BagLinkedList extends LinkedList
{
  private LinkedList<Item> list;

  // remove a random object -- one thing that does not come
  public Item remove()
  {
    Random gen = new Random();
    int index = gen.nextInt(this.size());
    return (Item) this.remove(index);
  }

  // Assume b is a linked list.  For each element in b, add it to myself.
  public BagLinkedList combine(BagLinkedList b)
  {
    // Have the LinkedList class return an iterator for b.
    ListIterator iterator = ((BagLinkedList) b).listIterator(0);
    while (iterator.hasNext())
      add(iterator.next());

    return this;
  }

  public boolean equals(BagInterface b)
  {
    return this.equals((BagLinkedList) b);
  }

  public void give(Item i, BagInterface b)
  {
    this.remove(i);
    ((BagLinkedList) b).add(i);
  }

  public String toString()
  {
    StringBuilder build = new StringBuilder();
    ListIterator iterator = this.listIterator(0);
    while (iterator.hasNext())
    {
      build.append("\t" + iterator.next().toString() + "\n");
    }
    return build.toString();
  }
}