publisher = dataStore.getAuthTokenPublisher(authToken);
if (publisher == null)
throw new AuthTokenRequiredException("authToken: "+authToken);
if (dataStore.isAuthTokenExpired(authToken))
throw new AuthTokenExpiredException("authToken: "+authToken);
// Token is valid so 'touch' so that it's
// internal 'expiration clock' is reset.
dataStore.touchAuthToken(authToken);