Help with Maatwebsite/Laravel-Excel

I am using Maatwebsite/Laravel-Excel to import excel file into my application. I want to use ExcelFile injections so that I can use it like this in my controller

class ExampleController extends Controller {

    public function importUserList(UserListImport $import)
    {
        // get the results
        $results = $import->get();
    }

}

In the Maatwebsite/Laravel-Excel example, it says to make a class like this to return and load excel file

class UserListImport extends \Maatwebsite\Excel\Files\ExcelFile {

    public function getFile()
    {
        return storage_path('exports') . '/file.csv';
    }

    public function getFilters()
    {
        return [
            'chunk'
        ];
    }

}

This method is used to return filename to be imported.

public function getFile()
    {
        return storage_path('exports') . '/file.csv';
    }

My issue is that filename is stored in database and is dynamic. How can I use the Import class with my dynamic filenames.

Docs for Maatwebsite/Laravel-Excel is available at http://www.maatwebsite.nl/laravel-excel/docs/import