@Override
 protected void handleChildTag() throws XMLStreamException, QuickFixException {
   ComponentDefRef ref = getDefRefHandler(getParentHandler()).getElement();
   // For now we only accept adding components to the default.
   if (AURA_HTML.equals(ref.getDescriptor().getQualifiedName())) {
     error("HTML tags are disallowed in attribute defaults, only components may be set.");
   }
   builder.addComponentRef(ref);
 }
 public DesignAttributeDefaultDefHandler(
     RootTagHandler<DesignDef> parentHandler,
     XMLStreamReader xmlReader,
     Source<?> source,
     boolean isInInternalNamespace,
     DefinitionService definitionService,
     ConfigAdapter configAdapter,
     DefinitionParserAdapter definitionParserAdapter) {
   super(
       parentHandler,
       xmlReader,
       source,
       isInInternalNamespace,
       definitionService,
       configAdapter,
       definitionParserAdapter);
   builder.setAccess(getAccess(isInInternalNamespace));
 }
 @Override
 protected DesignAttributeDefaultDef createDefinition() throws QuickFixException {
   return builder.build();
 }