/// <summary>
/// Moves the iterator to the previous element in the list.
/// </summary>
/// <returns>the previous element in the list.</returns>
public T previous()
{
modCheck();
my_index--;
my_parent.rangeCheck(my_index);
//check for double removal
if (my_removed)
{
my_removed = false;
}
//get the next value normally and return it
my_current = my_current.prev;
return(my_current.value);
}
/// <summary>
/// Removes an element from the list that was last returned by
/// a call to previous() or next().
/// </summary>
/// <returns>the removed element.</returns>
public T remove()
{
modCheck();
//check for double removal
if (my_removed)
{
throw new IllegalStateException("You cannot remove an item twice before advancing the iterator.");
}
my_removed = true;
T ret_value = my_current.value;
my_current = my_parent.removeNode(my_current);
my_index--;
return(ret_value);
}
/// <summary>
/// Moves the iterator to the next element after the current
/// iterator position.
/// </summary>
/// <returns>the next element in the list.</returns>
public T next()
{
modCheck();
my_index++;
my_parent.rangeCheck(my_index);
//check for double removal
if (my_removed)
{
my_removed = false;
}
//check whether we are on the first element, in this case just return the value
if (my_index == 0)
{
return(my_current.value);
}
else //advance normally here
{
my_current = my_current.next;
return(my_current.value);
}
}
/// <summary>
/// Sets up the node with an element, a link to the next and previous nodes.
/// </summary>
/// <param name="the_value">the element value.</param>
/// <param name="the_next">the next node link.</param>
/// <param name="the_prev">the previous node link.</param>
public LL_Node(T the_value, LL_Node <T> the_next, LL_Node <T> the_prev)
{
my_value = the_value;
my_next = the_next;
my_prev = the_prev;
}
private bool my_removed = false; //flag to avoid double removals
/// <summary>
/// Sets up the iterator with a link to the parent list.
/// </summary>
/// <param name="the_parent"></param>
public LL_ListIterator(LinkedList <T> the_parent)
{
my_current = the_parent.headNode();
my_parent = the_parent;
my_mod_count = my_parent.getModCount();
}
