content: /**
  * The interface of a generic linked list.
  */
  public interface LinkedList<T> {
      /**
      * @return true if the list is empty or false, otherwise
      */
      public boolean isEmpty();
  
      /**
      * @return the number of elements on the list
      */
      public int size();
  
      /**
      * Searches for a given element in the list.
      *
      * @param element
      *            the element being searched for
      * @return the element if it is in the list or null, otherwise
      */
      public T search(T element);
  
      /**
      * Inserts a new element at the end of the list. Null elements must be
      * ignored.
      *
      * @param element
      *            the element to be inserted
      */
      public void insert(T element);
  
      /**
      * Removes an element from the list. If the element does not exist the list
      * is not changed.
      *
      * @param element
      *            the element to be removed
      */
      public void remove(T element);
  
      /**
      * Returns an array containing all elements in the structure. The array does
      * not contain empty spaces (or null elements). The elements are put into
      * the array from the beginning to the end of the list.
      *
      * @return an array containing all elements in the structure in the order
      *         they appear
      */
      public T[] toArray();
  }
  