public function getCollapseClassNames()
    {
        $classes = $this->styles('navbar.collapse', 'collapse');
        
        if ($this->hasRows()) {
            $classes[] = $this->style('navbar.column');
        }
        
        if ($align = $this->ItemAlign) {
            $classes[] = $this->style(sprintf('navbar.item-align-%s', $align));
        }
        
        if ($justify = $this->ItemJustify) {
            $classes[] = $this->style(sprintf('navbar.item-justify-%s', $justify));
        }
        
        $this->extend('updateCollapseClassNames', $classes);
        
        return $classes;
    }