import com.sun.org.apache.xerces.internal.util.SAXInputSource; //导入依赖的package包/类
private Element resolveSchema(XMLInputSource schemaSource, XSDDescription desc,
        boolean mustResolve, Element referElement) {

    if (schemaSource instanceof DOMInputSource) {
        return getSchemaDocument(desc.getTargetNamespace(), (DOMInputSource) schemaSource, mustResolve, desc.getContextType(), referElement);
    } // DOMInputSource
    else if (schemaSource instanceof SAXInputSource) {
        return getSchemaDocument(desc.getTargetNamespace(), (SAXInputSource) schemaSource, mustResolve, desc.getContextType(), referElement);
    } // SAXInputSource
    else if (schemaSource instanceof StAXInputSource) {
        return getSchemaDocument(desc.getTargetNamespace(), (StAXInputSource) schemaSource, mustResolve, desc.getContextType(), referElement);
    } // StAXInputSource
    else if (schemaSource instanceof XSInputSource) {
        return getSchemaDocument((XSInputSource) schemaSource, desc);
    } // XSInputSource
    return getSchemaDocument(desc.getTargetNamespace(), schemaSource, mustResolve, desc.getContextType(), referElement);
}