question: private IgfsLogger ( String endpoint , String igfsName , String dir , int batchSize ) { A . notNull ( endpoint , "endpoint cannot be null" ) ; A . notNull ( dir , "dir cannot be null" ) ; A . ensure ( batchSize > 0 , "batch size cannot be negative" ) ; enabled = true ; this . endpoint = endpoint ; this . batchSize = batchSize ; pid = U . jvmPid ( ) ; File dirFile = new File ( dir ) ; A . ensure ( dirFile . isDirectory ( ) , "dir must point to a directory" ) ; A . ensure ( dirFile . exists ( ) , "dir must exist" ) ; file = new File ( dirFile , "igfs-log-" + igfsName + "-" + pid + ".csv" ) ; entries = new ConcurrentLinkedDeque8 < > ( ) ; cnt = new AtomicInteger ( ) ; useCnt = new AtomicInteger ( ) ; rwLock = new ReentrantReadWriteLock ( ) ; flushLock = new ReentrantLock ( ) ; flushCond = flushLock . newCondition ( ) ; flushWorker = new Thread ( new FlushWorker ( ) ) ; flushWorker . setDaemon ( true ) ; flushWorker . start ( ) ; }
target:  Construct normal file logger.