question: final boolean nonfairTryAcquire ( int acquires ) { final Thread current = Thread . currentThread ( ) ; int c = getState ( ) ; if ( c == 0 ) { if ( compareAndSetState ( 0 , acquires ) ) { setExclusiveOwnerThread ( current ) ; return true ; } } else if ( current == getExclusiveOwnerThread ( ) ) { int nextc = c + acquires ; if ( nextc < 0 ) throw new Error ( "Maximum lock count exceeded" ) ; setState ( nextc ) ; return true ; } return false ; }
target:  Performs non-fair tryLock.  tryAcquire is implemented in subclasses, but both need nonfair try for trylock method.