question: public void printUsage ( OutputStream os ) { int count = 0 ; PrintStream out = UTF8 . printStream ( os ) ; for ( String option : optionList ) { if ( optionGroups . containsKey ( count ) ) { out . println ( "  " + optionGroups . get ( count ) ) ; } count ++ ; if ( unlistedOptions . contains ( option ) ) { continue ; } out . print ( "    " ) ; StringBuilder buf = new StringBuilder ( ) ; buf . append ( option ) ; if ( optionExtraPartSynopsisMap . get ( option ) != null ) { String optionExtraPartSynopsis = optionExtraPartSynopsisMap . get ( option ) ; buf . append ( "[:" ) ; buf . append ( optionExtraPartSynopsis ) ; buf . append ( "]" ) ; } if ( requiresArgumentSet . contains ( option ) ) { buf . append ( " <" ) ; buf . append ( argumentDescriptionMap . get ( option ) ) ; buf . append ( ">" ) ; } printField ( out , buf . toString ( ) , maxWidth + 1 ) ; out . println ( optionDescriptionMap . get ( option ) ) ; } out . flush ( ) ; }
target:  Print command line usage information to given stream.