protected OAuthRegisteredService getRegisteredServiceByClientId(final String clientId) {
        return OAuth20Utils.getRegisteredOAuthServiceByClientId(this.servicesManager, clientId);
    }
Gets registered service by client id.

@param clientId the client id
@return the registered service by client id
support/cas-server-support-oauth-core-api/src/main/java/org/apereo/cas/support/oauth/validator/authorization/BaseOAuth20AuthorizationRequestValidator.java