@Override
  public void setPrincipal(Principal principal) {
    super.setPrincipal(principal);

    // Put the session into the region to serialize the principal
    if (getManager() != null) {
      // TODO convert this to a delta
      getManager().add(this);
      final Log logger = getDeltaSessionManager().getLogger();
      if (logger.isDebugEnabled()) {
        logger.debug(this + ": Cached principal: " + principal);
      }
    }
  }
Return the <code>HttpSession</code> for which this object is the facade.
extensions/geode-modules/src/main/java/org/apache/geode/modules/session/catalina/DeltaSession.java