question: public static String addTTDir ( final String fontPath , String failed ) { checkFontTablesInitialised ( ) ; final File currentDir = new File ( fontPath ) ; if ( ( currentDir . exists ( ) ) && ( currentDir . isDirectory ( ) ) ) { final String [ ] files = currentDir . list ( ) ; if ( files != null ) { for ( final String currentFont : files ) { addFontFile ( currentFont , fontPath ) ; } } } else { if ( failed == null ) { failed = fontPath ; } else { failed = failed + ',' + fontPath ; } } return failed ; }
target:  add a truetype font directory and contents to substitution