code: void setFeature( XMLReader reader,
                       String featureName,
                       boolean value ) {
          try {
              if (reader.getFeature(featureName) != value) {
                  reader.setFeature(featureName, value);
              }
          } catch (SAXException e) {
              getLogger().warn(e, "Cannot set feature " + featureName);
          }
      }
docs: Sets the reader's named feature to the supplied value, only if the feature is not already set to that value. This method
  does nothing if the feature is not known to the reader.
  
  @param reader the reader; may not be null
  @param featureName the name of the feature; may not be null
  @param value the value for the feature