class DBUserGroupCallbackImpl extends AbstractUserGroupInfo implements UserGroupCallback {

	public boolean existsGroup(String groupId) {
		if (groupId == null) {
			throw new IllegalArgumentException("GroupId cannot be null");
		}
		return checkExistence(this.config.getProperty(ROLES_QUERY), groupId);
	}

	public  DBUserGroupCallbackImpl(boolean activate);
	public  DBUserGroupCallbackImpl(Properties config);

}