@Override
    protected String getRegisteredServiceIdentifierFromRequest(final WebContext context) {
        val callContext = new CallContext(context, getConfigurationContext().getObject().getSessionStore());
        return getConfigurationContext().getObject().getRequestParameterResolver()
            .resolveClientIdAndClientSecret(callContext).getLeft();
    }
This is {@link AccessTokenRefreshTokenGrantRequestExtractor}.

@author Misagh Moayyed
@since 5.1.0
support/cas-server-support-oauth-core-api/src/main/java/org/apereo/cas/support/oauth/web/response/accesstoken/ext/AccessTokenRefreshTokenGrantRequestExtractor.java