public void setMaxConnectionsPerUser(Integer maxConnectionsPerUser) {
        this.maxConnectionsPerUser = maxConnectionsPerUser;
    }
Sets the maximum number of connections that can be established to this
connection group concurrently by any one user.

@param maxConnectionsPerUser
    The maximum number of connections that can be established to this
    connection group concurrently by any one user, zero if no
    restriction applies, or null if the default restrictions should be
    applied.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/connectiongroup/ConnectionGroupModel.java