private static void convertTagsAndAttributes(String ns,
                                               final List<? extends XmlTag> tags,
                                               final List<? extends XmlAttribute> attrs,
                                               Project project) {
    final int localNameIndex = ns.length() + 1;
    final int totalCount = tags.size() + attrs.size();

    final SequentialModalProgressTask progressTask = new SequentialModalProgressTask(
      project, XmlBundle.message("xml.progress.changing.to.default.namespace"), true);
    progressTask.setTask(new SequentialTask() {
      int tagIndex = 0;
      int attrIndex = 0;

      @Override
      public boolean isDone() {
        return tagIndex + attrIndex >= totalCount;
      }

      @Override
      public boolean iteration() {
        progressTask.getIndicator().setFraction(((double)(tagIndex + attrIndex)) / totalCount);
        ApplicationManager.getApplication().runWriteAction(() -> {
          if (tagIndex < tags.size()) {
            XmlTag tag = tags.get(tagIndex++);
            final String s = tag.getName().substring(localNameIndex);
            if (!s.isEmpty()) {
              tag.setName(s);
            }
          }
          else if (attrIndex < attrs.size()) {
            XmlAttribute attr = attrs.get(attrIndex++);
            //noinspection ConstantConditions
            attr.setValue(attr.getValue().substring(localNameIndex));
          }
        });

        return isDone();
      }
    });
    ProgressManager.getInstance().run(progressTask);
  }
private static void convertTagsAndAttributes(String ns,
                                               final List<? extends XmlTag> tags,
                                               final List<? extends XmlAttribute> attrs,
                                               Project project)