@Override
          public Stream open(String sourceUri, String encoding) throws IOException {
            final String s = reference(null, sourceUri);
            final File file = new File(outputFile.getParentFile(), s);
            if (file.exists()) {
              final String msg = RelaxngBundle.message("relaxng.convert-schema.dialog.file-exists.message", file.getAbsolutePath());
              final int choice = Messages.showYesNoDialog(myProject, msg, RelaxngBundle.message(
                "relaxng.convert-schema.dialog.file-exists.title"), Messages.getWarningIcon());
              if (choice == Messages.YES) {
                return super.open(sourceUri, encoding);
              } else if (choice == 1) {
                throw new CanceledException();
              }
            }
            return super.open(sourceUri, encoding);
          }
@Override
          public Stream open(String sourceUri, String encoding)