/**
  @author Adriano Luchetta
  @version 21-Nov-2005
  @version 3-Dic-2004
*/

import java.util.NoSuchElementException;

public class ListaSuArray implements List
{
  //variabili di istanza
  Object[] v;
  int vSize;

  //costruttore
  public ListaSuArray()
  {
    makeEmpty();
  }
  
  public void makeEmpty()
  {
    v = new Object[1];
    vSize = 0;
  }
  
  public boolean isEmpty()
  {
    return vSize == 0;
  }
  
  public int size()
  {
    return vSize;
  }

  public ListIterator getIterator()
  {
    return new ArrayIterator();
  }

  private class ArrayIterator implements ListIterator
  {
    private int position;

    public ArrayIterator()
    {
      position = -1;
    }

    public boolean hasNext()
    {
      return position + 1 < vSize;
    }

    public Object next() throws NoSuchElementException
    {
      if (!hasNext())
        throw new NoSuchElementException();

      return v[++position];
    }

    public void add(Object obj)
    {
      if (vSize == v.length)
      {
        Object[] vTmp = new Object[2 * vSize];

        for (int i = 0; i < vSize; i++)
          vTmp[i] = v[i];
         
        v = vTmp;
      }

      for (int i = vSize; i > position + 1; i--)
        v[i] = v[i-1];

      v[position + 1] = obj;
      vSize++;
    }

    public void remove() throws IllegalStateException
    {
      if (position == -1)
        throw new IllegalStateException();

      for (int i = position; i < vSize-1; i++)
        v[i] = v[i+1];

      vSize--;
      position--;
    }
  }
}