import javax.xml.bind.Element; //导入依赖的package包/类
protected final Element spawnWildcard( int memento, String uri, String local, String qname, Attributes atts )
        throws SAXException {
    UnmarshallingEventHandler ueh = context.getGrammarInfo().createUnmarshaller(uri,local,context);
    
    if(ueh!=null) {
        context.pushContentHandler(ueh,memento);
        ueh.enterElement(uri,local,qname,atts);
        return (Element)ueh.owner();
    } else {
        // if no class is available to unmarshal this element, discard
        // the sub-tree by feeding events to discarder.
        context.pushContentHandler( new Discarder(context), memento );
        context.getCurrentHandler().enterElement(uri,local,qname,atts);
        return null;    // return null so that the discarder will be ignored
    }
}