code: @CheckForNull
      public String extractMemcachedId( @Nonnull final String sessionId ) {
          final int idxDash = sessionId.indexOf( '-' );
          if ( idxDash < 0 ) {
              return null;
          }
          final int idxDot = sessionId.indexOf( '.' );
          if ( idxDot < 0 ) {
              return sessionId.substring( idxDash + 1 );
          } else if ( idxDot < idxDash ) /* The dash was part of the jvmRoute */ {
              return null;
          } else {
              return sessionId.substring( idxDash + 1, idxDot );
          }
      }
docs: Extract the memcached id from the given session id.
  
  @param sessionId
  the session id including the memcached id and eventually the
  jvmRoute.
  @return the memcached id or null if the session id didn't contain any
  memcached id.