On each request, the SiteSessionManager invokes its handleSiteRequest() method to iterate over its array of SiteRequestProcessor components and call each processor’s processSiteRequest() method. This method typically updates SiteSessionManager or SiteSession attributes, in accordance with current request properties. It has the following signature:

void processSiteRequest
   (SiteContext pSiteContext, DynamoHttpServletRequest pRequest)

The Oracle Commerce Platform installation provides one class that implements the SiteRequestProcessor interface, atg.multisite.LastSiteVisitedProcessor. Its implementation of processSiteRequest() sets the current session’s last-visited site in the SiteSessionManager's lastVisitedSite attribute.