code: public boolean disableFileWrite() {
          if (null == _disableFileWrite) {
              boolean b = (Boolean) get(ENGINE_FILE_WRITE_ENABLED);
              b = b && !gae();
              _disableFileWrite = !b;
          }
          return _disableFileWrite;
      }
docs: Return inversed value of {@link RythmConfigurationKey#ENGINE_FILE_WRITE_ENABLED}
  without lookup
  
  @return true if file write is disabled