private void writeAttributes(Element attrElements) throws WriteExternalException {
    List<TextAttributesKey> list = new ArrayList<TextAttributesKey>(myAttributesMap.keySet());
    Collections.sort(list);

    for (TextAttributesKey key : list) {
      TextAttributes defaultAttr =
          myParentScheme != null ? myParentScheme.getAttributes(key) : new TextAttributes();
      TextAttributesKey baseKey = key.getFallbackAttributeKey();
      TextAttributes defaultFallbackAttr =
          baseKey != null && myParentScheme instanceof AbstractColorsScheme
              ? ((AbstractColorsScheme) myParentScheme).getFallbackAttributes(baseKey)
              : null;
      TextAttributes value = myAttributesMap.get(key);
      if (!value.equals(defaultAttr) || defaultAttr == defaultFallbackAttr) {
        Element element = new Element(OPTION_ELEMENT);
        element.setAttribute(NAME_ATTR, key.getExternalName());
        if (baseKey == null || !value.isFallbackEnabled()) {
          Element valueElement = new Element(VALUE_ELEMENT);
          value.writeExternal(valueElement);
          element.addContent(valueElement);
          attrElements.addContent(element);
        } else if (defaultAttr != defaultFallbackAttr) {
          element.setAttribute(BASE_ATTRIBUTES_ATTR, baseKey.getExternalName());
          attrElements.addContent(element);
        }
      }
    }
  }
  private void writeColors(Element colorElements) {
    List<ColorKey> list = new ArrayList<ColorKey>(myColorsMap.keySet());
    Collections.sort(list);

    for (ColorKey key : list) {
      if (haveToWrite(key)) {
        Color value = myColorsMap.get(key);
        Element element = new Element(OPTION_ELEMENT);
        element.setAttribute(NAME_ATTR, key.getExternalName());
        element.setAttribute(
            VALUE_ELEMENT, value != null ? Integer.toString(value.getRGB() & 0xFFFFFF, 16) : "");
        colorElements.addContent(element);
      }
    }
  }