question: private void readUnlockedThread ( ) { final long thisThreadId = Thread . currentThread ( ) . getId ( ) ; final Integer entry = threadLockMap . get ( thisThreadId ) ; assert entry != null ; if ( entry . intValue ( ) == 1 ) { threadLockMap . remove ( thisThreadId ) ; } else { threadLockMap . put ( thisThreadId , entry . intValue ( ) - 1 ) ; } }
target:  Track the #of read locks by thread IFF this is a read/write index view.