@NotNull
 public XPathType getExpectedType(XPathExpression expr) {
   final XmlTag tag = PsiTreeUtil.getContextOfType(expr, XmlTag.class, true);
   if (tag != null && XsltSupport.isXsltTag(tag)) {
     final XsltElement element =
         XsltElementFactory.getInstance().wrapElement(tag, XsltElement.class);
     if (element instanceof XsltVariable) {
       return ((XsltVariable) element).getType();
     } else {
       final XmlAttribute attr = PsiTreeUtil.getContextOfType(expr, XmlAttribute.class, true);
       if (attr != null) {
         if (element instanceof XsltWithParam) {
           final XmlAttribute nameAttr = tag.getAttribute("name", null);
           if (nameAttr != null) {
             final XmlAttributeValue valueElement = nameAttr.getValueElement();
             if (valueElement != null) {
               final PsiReference[] references = valueElement.getReferences();
               for (PsiReference reference : references) {
                 final PsiElement psiElement = reference.resolve();
                 if (psiElement instanceof XsltVariable) {
                   return ((XsltVariable) psiElement).getType();
                 }
               }
             }
           }
         } else {
           final String name = attr.getName();
           return getTypeForTag(tag, name);
         }
       }
     }
   }
   return XPathType.UNKNOWN;
 }
 @Nullable
 public static Set<PsiType> getExpectedTypes(final CompletionParameters parameters) {
   final PsiExpression expr =
       PsiTreeUtil.getContextOfType(parameters.getPosition(), PsiExpression.class, true);
   if (expr != null) {
     final Set<PsiType> set = new THashSet<PsiType>();
     for (final ExpectedTypeInfo expectedInfo :
         JavaSmartCompletionContributor.getExpectedTypes(parameters)) {
       set.add(expectedInfo.getType());
     }
     return set;
   }
   return null;
 }
  public PsiFile[] getRelatedFiles(final XPathFile file) {

    final XmlAttribute attribute = PsiTreeUtil.getContextOfType(file, XmlAttribute.class, false);
    assert attribute != null;

    final PsiFile psiFile = attribute.getContainingFile();
    assert psiFile != null;

    final List<PsiFile> files = new ArrayList<PsiFile>();

    psiFile.accept(
        new XmlRecursiveElementVisitor() {
          @Override
          public void visitXmlAttribute(XmlAttribute attribute) {
            final PsiFile[] _files = XsltSupport.getFiles(attribute);
            for (PsiFile _file : _files) {
              if (_file != file) files.add(_file);
            }
          }
        });

    return PsiUtilCore.toPsiFileArray(files);
  }