*aHandler = new txUnknownHandler(mEs); break;
NS_ERROR("How can method not be known when root element is?"); return NS_ERROR_UNEXPECTED;
txToDocHandlerFactory::createHandlerWith(txOutputFormat* aFormat,                                         txAXMLEventHandler** aHandler){    *aHandler = nsnull;    switch (aFormat->mMethod) {        case eMethodNotSet:        case eXMLOutput:        {            *aHandler = new txUnknownHandler(mEs);            break;        }        case eHTMLOutput:        {            *aHandler = new txMozillaXMLOutput(EmptyString(),                                               kNameSpaceID_None,                                               aFormat, mSourceDocument,                                               mResultDocument, mObserver);            break;        }        case eTextOutput:        {            *aHandler = new txMozillaTextOutput(mSourceDocument,                                                mResultDocument,                                                mObserver);            break;        }    }    NS_ENSURE_TRUE(*aHandler, NS_ERROR_OUT_OF_MEMORY);    return NS_OK;}