public Set<String> getConnectionGroupIdentifiers(UserData userData) {

        // The only connection group available is the root group
        return Collections.singleton(UserContext.ROOT_CONNECTION_GROUP);

    }
Returns the identifiers of all connection groups readable by the user
whose data is given by the provided UserData object. This will always be
a set containing only the root connection group identifier. The
JSONAuthenticationProvider does not define any other connection groups.

@param userData
    All data associated with the user whose accessible connection group
    identifiers are being retrieved.

@return
    A set containing the identifiers of all connection groups readable
    by the user whose data is given by the provided UserData object.
extensions/guacamole-auth-json/src/main/java/org/apache/guacamole/auth/json/user/UserDataService.java