// Search given shape and set current to it if found
public bool Search(AShape s)
{
if (s != null)
{
DoublyNode t = current;
Set_current_first();
for (bool cond = !Is_empty(); cond;
cond = Step_forward())
{
if (Current.Shape == s)
{
return(true);
}
}
current = t;
}
Notify();
return(false);
}
// Add new shape to the front of the list
public bool Push_front(AShape shape)
{
if (shape == null)
{
return(false);
}
DoublyNode fresh = new DoublyNode(shape);
if (count > 0)
{
head.prev = fresh;
fresh.next = head;
head = fresh;
}
else
{
tail = fresh;
head = fresh;
}
current = head;
++count;
Notify();
return(true);
}
// Add new shape to the back of the list
public bool Push_back(AShape shape)
{
if (shape == null)
{
return(false);
}
DoublyNode fresh = new DoublyNode(shape);
if (count > 0)
{
fresh.prev = tail;
tail.next = fresh;
tail = fresh;
}
else
{
tail = fresh;
head = fresh;
}
current = tail;
++count;
Notify();
return(true);
}
public DoublyNode(AShape shape)
{
this.shape = shape;
prev = null;
next = null;
}