JavaFX Primer - JavaFX: Developing Rich Internet Applications - page 39

(within.layoutBounds.width -
node.layoutBounds.width)/2.0 -
node.layoutBounds.minX;
}
protected bound function centerY(node: Node,
within: Node) : Number {
(within.layoutBounds.height -
node.layoutBounds.height)/2.0 -
node.layoutBounds.minY;
}
}
Subclasses that want to implement their own version of the mixin function must
use the override keyword when declaring the function. For instance, the follow-
ing code shows a subclass that implements its own version of the centerX()
function from the Positioner mixin class.
public class My Positioner extends Positioner {
public override bound function centerX(node: Node,
within: Node) : Number {
(within.boundsInParent.width -
node.boundsInParent.width )/2.0;
}
}
If the mixin function does not have a default implementation, it must be declared
abstract and the subclass must override this function to provide an implementa-
tion. For instance, the following code shows an abstract function added to the
Positioner mixin class.
public abstract function bottomY(node: Node,
within: Node, padding: Number) : Number;
The subclass must implement this function using the override keyword, as
shown in the following listing.
public class My Positioner extends Positioner {
public override function bottomY(node: Node,
within: Node, padding: Number) : Number {
within.layoutBounds.height - padding -
node.layoutBounds.height;
}
}
If two mixins have the same function signature or variable name, the system
resolves to the function or variable based on which mixin is declared first in the