/**
 * Description: Works just like java.util.ArrayList, except it will refuse to
 * add an element if it is equal to an element already appearing in the
 * ArrayListSet. In other words, it's an ArrayList which maintains uniqueness
 * like java.util.Set does.
 *
 * @author  Kerry M. Soileau
 * <blockquote><pre>
 * ksoileau@wt.net
 * http://web.wt.net/~ksoileau/index.htm
 * </pre></blockquote>
 * @version 1.3
 */
 import java.util.*;

public class ArrayListSet extends ArrayList implements Set
{
/**
  * Constructs a new, empty ArrayListSet.
  */
  public ArrayListSet()
  {
  }

/**
  * Constructs a new set containing space for the specified number of objects.
  *
  * @param n The capacity of the new set.
  */
  public ArrayListSet(int n)
  {
    super(n);
  }

/**
  * Constructs a new set containing the elements in the specified
  * collection.
  *
  * @param c The elements that will comprise the new set.
  */
  public ArrayListSet(Collection c)
  {
    addAll(c);
  }

/**
  * Adds the specified element to this set if it is not already present.
  *
  * @param o element to be added to this set.
  * @return <tt>true</tt> if the set did not already contain the specified
  *         element.
  */
  public boolean add(Object o)
  {
    for(int i=0;i<this.size();i++)
    {
      Object obj=this.get(i);
      if(obj.equals(o))
        return false;
    }
    super.add(o);
    return true;
  }

/**
  * Adds all of the elements in the specified collection to this set.
  *
  * @param c elements to be added
  * @return <tt>true</tt> if this set changed as a result of the call.
  */
  public boolean addAll(Collection c)
  {
    boolean changed=false;
    if (c.size() > 0)
    {
      Iterator it=c.iterator();
      while(it.hasNext())
      {
        Object nextobj=it.next();
        boolean res=this.add(nextobj);
        if(res) changed=true;
      }
    }
    return changed;
  }

/**
  * Adds the specified element to this set if it is not already present.
  *
  * @param o element to be added to this set.
  */
  public void addElement(Object o)
  {
    for(int i=0;i<this.size();i++)
    {
      if(this.get(i).equals(o))
        return;
    }
    super.add(o);
  }

//Simple demo --- may be deleted at will.
  public static void main(String[] args)
  {
    ArrayListSet vectorSet1 = new ArrayListSet();
    vectorSet1.add("Leda");
    vectorSet1.add("Tyndareus");
    vectorSet1.add("Helen");
    vectorSet1.add("");
    vectorSet1.add("Thyestes");
    vectorSet1.add("Tyndareus");
    vectorSet1.add("Tantalus");
    vectorSet1.add("");
    vectorSet1.add("Leda");
    vectorSet1.add("Tyndareus");
    vectorSet1.add(new Integer(32));
    vectorSet1.add("Agamemnon");
    vectorSet1.add("Aerope");
    vectorSet1.add("Leda");
    vectorSet1.add(new Integer(33));
    vectorSet1.add("Thyestes");
    for(int i=0;i<vectorSet1.size();i++)
      System.out.println(vectorSet1.get(i));
  }
}