code: public CmsSite matchSite(CmsSiteMatcher matcher) {
  
          CmsSite site = m_siteMatcherSites.get(matcher);
          if (site == null) {
              // return the default site (might be null as well)
              site = m_defaultSite;
          }
          return site;
      }
docs: Return the configured site that matches the given site matcher,
  or the default site if no sites matches.<p>
  
  @param matcher the site matcher to match the site with
  @return the matching site, or the default site if no sites matches