Thread: need help with a list class

iv created a small class that creates linked lists. however i was told to make it more efficient. apparently its inefficient bcuz we have to start at the beginning of the linked list everytime we do a search..how can i make the class "remember" its previous position and start from there...this should allow the position method to start searching from the given position..

how do i do this...code follows:

public class IntegerList
 
  { private class ListNode
 
      { public int data;
 
        public ListNode next;
 
      } // inner class ListNode
 
 
 
    /** Reference to the first ListNode in a IntegerList.
 
      */
 
    private ListNode first;
 
    /** Number of elements in a IntegerList.
 
      */
 
    private int numElements;
 
 
 
    /** Create an empty IntegerList.
 
      * <BR><I>Postcondition:</I> The list is empty.
 
      */
 
    public IntegerList ()
 
      { first = null;
 
        numElements = 0;
 
      } // IntegerList constructor
 
 
 
    public void add (int item, int position)
 
      { assert position >= 0 : "Position is non-negative";
 
        ListNode node = new ListNode();
 
        node.data = item;
 
        ListNode curr = first,
 
                 prev = null;
 
        for (int k = 0; k < position && curr != null; k++) // Find position
 
          { prev = curr;
 
            curr = curr.next;
 
          }
 
        node.next = curr;
 
        if (prev != null)
 
          prev.next = node;
 
        else
 
          first = node;
 
        numElements++;
 
     } // add
 
 
 
    /** Place a new item at the end of an IntegerList.
 
      * <BR><I>Postcondition:</I> The value <CODE>item</CODE> appears at
 
      * the end of the list.
 
      * @param item The integer value to be added to the list.
 
      */
 
    public void add (int item)
 
      { add(item, numElements);
 
      } // add
 
 
 
    /** Remove the item at a given position in an IntegerList.
 
      * <BR><I>Precondition:</I> The position is that of a valid item.
 
      * <BR><I>Postcondition:</I> The item at <CODE>position</CODE> has been
 
      *  removed from the list.
 
      * @param position The position of the item to be removed from the
 
      * list.
 
      * @throws AssertionError If <CODE>position</CODE> is invalid.
 
      */
 
    public void remove (int position)
 
      { assert position >= 0 && position < numElements : "Position is in range";
 
        ListNode curr = first,
 
                 prev = null;
 
        for (int k = 0; curr != null && k < position; k++)
 
          { prev = curr;
 
            curr = curr.next;
 
          }
 
        assert curr != null;
 
        if (prev != null)
 
          prev.next = curr.next;
 
        else
 
          first = curr.next;
 
        numElements--;
 
      } // remove
 
 
 
    /** Return the current number of elements in an IntegerList.
 
      * @return The number of elements in the list.
 
      */
 
    public int length ()
 
      { return numElements;
 
      } // length
 
 
 
    /** Retrieve an element from an IntegerList.
 
      * <BR><I>Precondition:</I> <CODE>index</CODE> is in range.
 
      * @return The element at position <CODE>index</CODE> in the list.
 
      * @throws AssertionError If <CODE>index</CODE> is invalid.
 
      */
 
    public int get (int index)
 
      { assert (index >= 0 && index < numElements) : "Index is in range";
 
        ListNode curr = first;
 
        for (int k = 0; curr != null && k < index; k++)
 
          curr = curr.next;
 
        assert curr != null;
 
        return curr.data;
 
      } // get
 
 
 
    /** Change the value of an element in an IntegerList.
 
      * <BR><I>Precondition:</I> <CODE>index</CODE> is in range.
 
      * @param index The position of the item to be changed in the list.
 
      * @param item The new value for the item.
 
      * @throws AssertionError If <CODE>index</CODE> is invalid.
 
      */
 
    public void set (int index, int item)
 
      { assert (index >= 0 && index < numElements) : "Index is in range";
 
        ListNode curr = first;
 
        for (int k = 0; curr != null && k < index; k++)
 
          curr = curr.next;
 
        assert curr != null;
 
        curr.data = item;
 
      } // get
 
 
 
    /** Find item in an IntegerList.
 
      * @param item The item to be searched for.
 
      * @return The position of this item if it is found, otherwise -1
 
      */
 
    public int position (int item)
 
      { ListNode curr = first;
 
        int k;
 
        for (k = 0; curr != null && curr.data != item; k++, curr = curr.next)
 
          ; // Search for item in IntegerList
 
        if (curr == null) // item was not found
 
          return -1;
 
        else
 
          return k;
 
      } // position
 
 
	public int position (int item, int pos)
 
      { ListNode curr = first;
 
        int k;
	for (int i = 0; i<=pos;i++)
	curr = curr.next();
       for (k = pos; curr != null && curr.data != item; k++, curr =curr.next)
 
          ; // Search for item in IntegerList
 
        if (curr == null) // item was not found
 
          return -1;
 
        else
 
          return k;
 
      }
 
    /** Return string representation of the IntegerList.
 
      * The format is: <CODE>[ <I>item</I>, <I>item</I>, ... ]</CODE>
 
      * @return A string representing the contents of this list
 
      */
 
    public String toString ()
 
      { StringBuffer s = new StringBuffer("[");
 
        for (ListNode curr = first; curr != null; curr = curr.next)
 
          { s.append("" + curr.data);
 
            if (curr.next != null)
 
              s.append(", ");
 
          }
 
        s.append("]");
 
        return s.toString();
 
      } // toString
 
 
 
  } // class IntegerList