question: private PeriodFormatterBuilder appendSuffix ( PeriodFieldAffix suffix ) { final Object originalPrinter ; final Object originalParser ; if ( iElementPairs . size ( ) > 0 ) { originalPrinter = iElementPairs . get ( iElementPairs . size ( ) - 2 ) ; originalParser = iElementPairs . get ( iElementPairs . size ( ) - 1 ) ; } else { originalPrinter = null ; originalParser = null ; } if ( originalPrinter == null || originalParser == null || originalPrinter != originalParser || ! ( originalPrinter instanceof FieldFormatter ) ) { throw new IllegalStateException ( "No field to apply suffix to" ) ; } clearPrefix ( ) ; FieldFormatter newField = new FieldFormatter ( ( FieldFormatter ) originalPrinter , suffix ) ; iElementPairs . set ( iElementPairs . size ( ) - 2 , newField ) ; iElementPairs . set ( iElementPairs . size ( ) - 1 , newField ) ; iFieldFormatters [ newField . getFieldType ( ) ] = newField ; return this ; }
target:  Append a field suffix which applies only to the last appended field. If the field is not printed, neither is the suffix.