Method display

/**
 * Execute and display a template script.
 *
 * @param   string  $tpl  The name of the template file to parse; automatically searches through the template paths.
 *
 * @return  void|boolean
 *
 * @since   3.2
 * @throws  \Exception
 */
public function display($tpl = null)
{
    $state = $this->get('State');
    $items = $this->get('Items');
    $parent = $this->get('Parent');
    $app = Factory::getApplication();
    // Check for errors.
    if (\count($errors = $this->get('Errors'))) {
        $app->enqueueMessage($errors, 'error');
        return false;
    }
    if ($items === false) {
        $app->enqueueMessage(Text::_('JGLOBAL_CATEGORY_NOT_FOUND'), 'error');
        return false;
    }
    if ($parent == false) {
        $app->enqueueMessage(Text::_('JGLOBAL_CATEGORY_NOT_FOUND'), 'error');
        return false;
    }
    $params =& $state->params;
    $items = array($parent->id => $items);
    // Escape strings for HTML output
    $this->pageclass_sfx = htmlspecialchars($params->get('pageclass_sfx', ''), ENT_COMPAT, 'UTF-8');
    $this->maxLevelcat = $params->get('maxLevelcat', -1) < 0 ? PHP_INT_MAX : $params->get('maxLevelcat', PHP_INT_MAX);
    $this->params =& $params;
    $this->parent =& $parent;
    $this->items =& $items;
    $this->prepareDocument();
    parent::display($tpl);
}