public String[] knownNamespaces() { final PsiElement parentElement = getParent(); BidirectionalMap<String, String> map = initNamespaceMaps(parentElement); Set<String> known = Collections.emptySet(); if (map != null) { known = new HashSet<String>(map.values()); } if (parentElement instanceof XmlTag) { if (known.isEmpty()) return ((XmlTag) parentElement).knownNamespaces(); ContainerUtil.addAll(known, ((XmlTag) parentElement).knownNamespaces()); } else { XmlExtension xmlExtension = XmlExtension.getExtensionByElement(this); if (xmlExtension != null) { final XmlFile xmlFile = xmlExtension.getContainingFile(this); if (xmlFile != null) { final XmlTag rootTag = xmlFile.getRootTag(); if (rootTag != null && rootTag != this) { if (known.isEmpty()) return rootTag.knownNamespaces(); ContainerUtil.addAll(known, rootTag.knownNamespaces()); } } } } return ArrayUtil.toStringArray(known); }