public function delete()
    {

        if (!isset($this->params['index']))
            throw new exceptions\RuntimeException("Index cannot be empty.");

        $index = implode(',', $this->params['index']);

        $command = new Command();
        $command->index($index)
            ->action('delete');

        $this->batch->clearCommands();
        $this->batch->addCommand($command);

        $ret = parent::execute();

        return $ret[0];
    }