class EcmFileParticipantService {

    @Transactional(rollbackFor = Exception.class)
    public EcmFile setFileParticipantsFromParentFolder(EcmFile file)
    {
        if (file.getFolder() == null)
        {
            throw new IllegalStateException("File doesn't have parent folder!");
        }

        setFileParticipants(file, file.getFolder().getParticipants());

        // modify the instance to trigger the Solr transformers
        file.setModified(new Date());
        return getFileDao().save(file);
    }

}