protected boolean isGrantTypeSupportedBy(final OAuthRegisteredService registeredService,
                                             final String type, final boolean rejectUndefined) {
        return OAuth20RequestParameterResolver.isAuthorizedGrantTypeForService(type, registeredService, rejectUndefined);
    }
This is {@link BaseOAuth20TokenRequestValidator}.

@author Misagh Moayyed
@since 5.3.0
support/cas-server-support-oauth-core-api/src/main/java/org/apereo/cas/support/oauth/validator/token/BaseOAuth20TokenRequestValidator.java