question: public static void updateProperty ( Configuration conf , String prefix , String alternativePrefix , String key , Properties props , String propsKey , boolean required ) throws ConfigurationParseException { String val = conf . get ( prefix + key ) ; if ( val == null ) { val = conf . get ( alternativePrefix + key ) ; LOG . trace ( "Trying alternative key {}{}" , alternativePrefix , key ) ; } if ( required && val == null ) { throw new ConfigurationParseException ( "Missing mandatory configuration: " + key ) ; } if ( val != null ) { props . setProperty ( propsKey , val . trim ( ) ) ; } }
target:  Read key from core-site.xml and parse it to Swift configuration