class EcmFileParticipantService {

    @Transactional(rollbackFor = Exception.class)
    public List<AcmParticipant> setFolderParticipants(Long objectId, List<AcmParticipant> participants)
            throws AcmParticipantsException
    {
        validateFileParticipants(participants);

        AcmFolder folder = getFolderService().findById(objectId);
        getFolderDao().getEm().detach(folder);
        setFolderParticipants(folder, participants, folder.getRestricted());
        // modify the instance to trigger the Solr transformers
        folder.setModified(new Date());
        AcmFolder savedFolder = getFolderService().saveFolder(folder);

        return savedFolder.getParticipants();
    }

}