code: public double getQualityValue() {
          String qualityFactory = getParameter(PARAM_QUALITY_FACTOR);
          return (qualityFactory != null ? Double.parseDouble(unquote(qualityFactory)) : 1D);
      }
docs: Return the quality value, as indicated by a {@code q} parameter, if any. Defaults to {@code 1.0}.
  
  @return the quality factory.