@Override
      public void invoke(@NotNull Project project, @NotNull Editor editor, @NotNull PsiFile file) {
        final XmlDocument document = findSuitableXmlDocument(file);
        if (document != null) {
          final @NonNls StringBuilder buffer = new StringBuilder();
          buffer.append("<!DOCTYPE ").append(document.getRootTag().getName()).append(" [\n");
          buffer.append(XmlUtil.generateDocumentDTD(document, true));
          buffer.append("]>\n");
          XmlFile tempFile;
            try{
              final XmlProlog prolog = document.getProlog();
              final PsiElement childOfType = PsiTreeUtil.getChildOfType(prolog, XmlProcessingInstruction.class);
              if (childOfType != null) {
                final String text = childOfType.getText();
                buffer.insert(0,text);
                final PsiElement nextSibling = childOfType.getNextSibling();
                if (nextSibling instanceof PsiWhiteSpace) {
                  buffer.insert(text.length(),nextSibling.getText());
                }
              }
              tempFile = (XmlFile)PsiFileFactory.getInstance(file.getProject()).createFileFromText("dummy.xml", buffer.toString());
              prolog.replace(tempFile.getDocument().getProlog());
            }
          catch (IncorrectOperationException e) {
            LOG.error(e);
          }
        }
      }
@Override
      public void invoke(@NotNull Project project, @NotNull Editor editor, @NotNull PsiFile file)