public static boolean hasConfiguration(String subdomain) {
        return getConfiguration(subdomain, true) != null;
    }
Returns true if there is a configuration for the specified subdomain. This
checking can be used as an indirect way of checking that the specified
subdomain belongs to an external component.

@param subdomain the subdomain of the external component.
@return true if there is a configuration for the specified subdomain.
xmppserver/src/main/java/org/jivesoftware/openfire/component/ExternalComponentManager.java