public static MappingScriptProxy getEmptyUserMappingModel(String source, String dest) {
    try { // usar getSchema??
      URL url = new URL(source);
      XMLSchema sxml = getXSDSchema(url);
      url = new URL(dest);
      XMLSchema dxml = getXSDSchema(url);

      MappingScript mapping = getEmptyMapping(sxml, dxml, null);
      Mapping2UIAdapter adapter = new Mapping2UIAdapter();
      return adapter.adapt(mapping);
    } catch (IOException e) {
      e.printStackTrace();
      return null;
    }
  }
  public static MappingScriptProxy getExistingMappingModel(TransformationUI transformationUI) {
    try {
      File xmapDir =
          ConfigSingleton.getRepoxContextUtil()
              .getRepoxManager()
              .getMetadataTransformationManager()
              .getXmapDir();
      String mapFilePath =
          xmapDir.getPath()
              + File.separator
              + FilenameUtils.removeExtension(transformationUI.getXslFilePath())
              + ".xmap";

      URL tmp = new URL(transformationUI.getSourceSchema());
      XMLSchema source = getXSDSchema(tmp);
      tmp = new URL(transformationUI.getDestSchema());
      XMLSchema target = getXSDSchema(tmp);
      MappingScript mapping = getMapping(source, target, mapFilePath);
      return new Mapping2UIAdapter().adapt(mapping);
    } catch (IOException e) {
      e.printStackTrace();
      return null;
    }
  }