code: public void modifyingRequest( final String requestId ) {
          if ( _log.isDebugEnabled() ) {
              _log.debug( "Registering modifying request: " + requestId );
          }
          incrementOrPut( _blacklist, requestId );
          _readOnlyRequests.remove( requestId );
      }
docs: Registers the given requestURI as a modifying request, which can be seen as a blacklist for
  readonly requests. There's a limit on number and time for modifying requests beeing stored.
  @param requestId the request uri to track.