question: private static String nodeName ( String dirName ) { if ( dirName . charAt ( 0 ) != '_' ) return dirName ; byte a [ ] = Base64 . altBase64ToByteArray ( dirName . substring ( 1 ) ) ; StringBuffer result = new StringBuffer ( a . length / 2 ) ; for ( int i = 0 ; i < a . length ; ) { int highByte = a [ i ++ ] & 0xff ; int lowByte = a [ i ++ ] & 0xff ; result . append ( ( char ) ( ( highByte << 8 ) | lowByte ) ) ; } return result . toString ( ) ; }
target:  Returns the node name corresponding to the specified directory name. (Inverts the transformation of dirName(String).