public boolean isPreferredConnection(String identifier) {
        return preferredConnections.contains(identifier);
    }
Returns whether the connection having the given identifier has been
marked as preferred for this user's current Guacamole session. A
preferred connection is always chosen in favor of other connections when
it is a child of a balancing connection group.

@param identifier
    The identifier of the connection to test.

@return
    true if the connection having the given identifier has been marked
    as preferred, false otherwise.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/user/ModeledAuthenticatedUser.java