public Object[] get(final PsiElement context, CompletionContext completionContext) {
      XmlFile containingFile = null;
      XmlFile descriptorFile = null;
      final XmlTag tag = PsiTreeUtil.getParentOfType(context, XmlTag.class);

      if (tag != null) {
        containingFile = (XmlFile) tag.getContainingFile();
        descriptorFile = findDescriptorFile(tag, containingFile);
      } else {
        final XmlDocument document = PsiTreeUtil.getParentOfType(context, XmlDocument.class);

        if (document != null) {
          containingFile = (XmlFile) document.getContainingFile();

          final FileType ft = containingFile.getFileType();

          if (ft != StdFileTypes.XML) {
            final String namespace =
                ft == StdFileTypes.XHTML || ft == StdFileTypes.JSPX
                    ? XmlUtil.XHTML_URI
                    : XmlUtil.HTML_URI;
            final XmlNSDescriptor nsDescriptor = document.getDefaultNSDescriptor(namespace, true);

            if (nsDescriptor != null) {
              descriptorFile = nsDescriptor.getDescriptorFile();
            }
          }
        }
      }

      if (descriptorFile != null) {
        final List<Object> results = new ArrayList<Object>();
        final boolean acceptSystemEntities = containingFile.getFileType() == StdFileTypes.XML;

        final PsiElementProcessor processor =
            new PsiElementProcessor() {
              public boolean execute(@NotNull final PsiElement element) {
                if (element instanceof XmlEntityDecl) {
                  final XmlEntityDecl xmlEntityDecl = (XmlEntityDecl) element;
                  if (xmlEntityDecl.isInternalReference() || acceptSystemEntities) {
                    final String name = xmlEntityDecl.getName();
                    final Object _item = getLookupItem(xmlEntityDecl);
                    results.add(_item == null ? name : _item);
                  }
                }
                return true;
              }
            };

        XmlUtil.processXmlElements(descriptorFile, processor, true);
        if (descriptorFile != containingFile && containingFile.getFileType() == StdFileTypes.XML) {
          final XmlProlog element = containingFile.getDocument().getProlog();
          if (element != null) XmlUtil.processXmlElements(element, processor, true);
        }

        return ArrayUtil.toObjectArray(results);
      }

      return ArrayUtil.EMPTY_OBJECT_ARRAY;
    }
 public static XmlFile findDescriptorFile(final XmlTag tag, final XmlFile containingFile) {
   final XmlElementDescriptor descriptor = tag.getDescriptor();
   final XmlNSDescriptor nsDescriptor = descriptor != null ? descriptor.getNSDescriptor() : null;
   XmlFile descriptorFile =
       nsDescriptor != null
           ? nsDescriptor.getDescriptorFile()
           : containingFile.getDocument().getProlog().getDoctype() != null ? containingFile : null;
   if (nsDescriptor != null
       && (descriptorFile == null
           || descriptorFile.getName().equals(containingFile.getName() + ".dtd"))) {
     descriptorFile = containingFile;
   }
   return descriptorFile;
 }