Can I override func mouseDown Without Subclassing?

Can I override func mouseDown only for a specific instance of NSView without subclassing?

I can do something like this using lambda in Java (see below), but can I do something like this using closure in Swift?

something.addMouseListener(new MouseAdapter() {
    @Override public void mouseReleased(MouseEvent e) {
        ...
    }

    @Override public void mousePressed(MouseEvent e) {
        ...
    }
});