/**
 * ListADT defines the interface to a general list collection. Specific
 * types of lists will extend this interface to complete the
 * set of necessary operations.
 * @author Dr. Lewis
 * @author Dr. Chase
 * @version 1.0, 08/13/08
 */

import java.util.Iterator;

public interface ListADT<T>
{

   /**  
    * Removes and returns the first element from this list. 
    * 
    * @return  the first element from this list
    */

   public T removeFirst ();

   /**  
    * Removes and returns the last element from this list. 
    *
    * @return  the last element from this list
    */

   public T removeLast ();

   /**  
    * Removes and returns the specified element from this list. 
    *
    * @param element  the element to be removed from the list
    */

   public T remove (T element);

   /**  
    * Returns a reference to the first element in this list. 
    *
    * @return  a reference to the first element in this list
    */

   public T first ();

   /**  
    * Returns a reference to the last element in this list. 
    *
    * @return  a reference to the last element in this list
    */

   public T last ();

   /**  
    * Returns true if this list contains the specified target element. 
    *
    * @param target  the target that is being sought in the list
    * @return        true if the list contains this element
    */

   public boolean contains (T target);

   /**  
    * Returns true if this list contains no elements. 
    *
    * @return  true if this list contains no elements
    */

   public boolean isEmpty();

   /**  
    * Returns the number of elements in this list. 
    *
    * @return  the integer representation of number of elements in this list
    */

   public int size();

   /**  
    * Returns an iterator for the elements in this list. 
    *
    * @return  an iterator over the elements in this list
    */

   public Iterator<T> iterator();

   /**  
    * Returns a string representation of this list. 
    *
    * @return  a string representation of this list
    */

   public String toString();

}