Set<String> (PsiFile psiFile) { final XmlDocument document = ((XmlFile)psiFile).getDocument(); if (document != null) { final XmlTag rootTag = document.getRootTag(); if (rootTag != null) { final Set<String> list = new HashSet<>(); processReferences(rootTag.findSubTags("include", XsltSupport.XSLT_NS), list); processReferences(rootTag.findSubTags("import", XsltSupport.XSLT_NS), list); return list; } } return Collections.emptySet(); }