private OAuth20RefreshTokenExpirationPolicy buildExpirationPolicyFor(final long timeout) {
        if (casProperties.getTicket().isTrackDescendantTickets()) {
            return new OAuth20RefreshTokenExpirationPolicy(timeout);
        }
        return new OAuth20RefreshTokenStandaloneExpirationPolicy(timeout);
    }
To ticket expiration policy.

@return the expiration policy
support/cas-server-support-oauth-core-api/src/main/java/org/apereo/cas/ticket/refreshtoken/OAuth20RefreshTokenExpirationPolicyBuilder.java