public Builder setHostnameForClients(final String hostnameForClients) {
      if (isBlank(hostnameForClients)) {
        throw new IllegalArgumentException(
            "The hostname used by clients to connect to the Locator must have an argument if the --hostname-for-clients command-line option is specified!");
      }
      this.hostnameForClients = hostnameForClients;
      return this;
    }
Sets the hostname used by clients to lookup the Locator.

@param hostnameForClients a String indicating the hostname Locator binding used in client
       lookups.
@return this Builder instance.
@throws IllegalArgumentException if the hostname was not specified (is blank or empty), such
        as when the --hostname-for-clients command-line option may have been specified
        without any argument.
@see #getHostnameForClients()
geode-core/src/main/java/org/apache/geode/distributed/LocatorLauncher.java