question: public static boolean isPairedEndDirectory ( final File dir ) { if ( dir == null || ! dir . exists ( ) || ! dir . isDirectory ( ) ) { return false ; } final File lDir = new File ( dir , "left" ) ; final File rDir = new File ( dir , "right" ) ; return lDir . exists ( ) && rDir . exists ( ) && lDir . isDirectory ( ) && rDir . isDirectory ( ) ; }
target:  Tells you if the directory passed in contains a paired end SDF left / right folder