private SchemaFactory loadFromProperty( String keyName, String resourceName, InputStream in )
        throws IOException {
        debugPrintln("Reading "+resourceName );

        Properties props=new Properties();
        props.load(in);
        in.close();
        String factoryClassName = props.getProperty(keyName);
        if(factoryClassName != null){
            debugPrintln("found "+keyName+" = " + factoryClassName);
            return createInstance(factoryClassName);
        } else {
            debugPrintln(keyName+" is not in the property file");
            return null;
        }
    }