concurrency

问题 It seems import Queue Queue.Queue().get(timeout=10) is keyboard interruptible (ctrl-c) whereas import Queue Queue.Queue().get() is not. I could always create a loop; import Queue q = Queue() while True: try: q.get(timeout=1000) except Queue.Empty: pass but this seems like a strange thing to do. So, is there a way of getting an indefinitely waiting but keyboard interruptible Queue.get()? 回答1: Queue objects have this behavior because they lock using Condition objects form the threading module.

问题 It seems import Queue Queue.Queue().get(timeout=10) is keyboard interruptible (ctrl-c) whereas import Queue Queue.Queue().get() is not. I could always create a loop; import Queue q = Queue() while True: try: q.get(timeout=1000) except Queue.Empty: pass but this seems like a strange thing to do. So, is there a way of getting an indefinitely waiting but keyboard interruptible Queue.get()? 回答1: Queue objects have this behavior because they lock using Condition objects form the threading module.

问题 It seems import Queue Queue.Queue().get(timeout=10) is keyboard interruptible (ctrl-c) whereas import Queue Queue.Queue().get() is not. I could always create a loop; import Queue q = Queue() while True: try: q.get(timeout=1000) except Queue.Empty: pass but this seems like a strange thing to do. So, is there a way of getting an indefinitely waiting but keyboard interruptible Queue.get()? 回答1: Queue objects have this behavior because they lock using Condition objects form the threading module.

问题 I have wrote code to understand CyclicBarrier. My application emulates election. Each rounds selects candidate with small votes and this candidate eliminates from the race for victory. source: class ElectoralCommission { public volatile boolean hasWinner; public volatile String winner; private List<String> candidates; private Map<String, Integer> results = new ConcurrentHashMap<>(); ElectoralCommission(List<String> candidates) { this.candidates = candidates; } public void acceptVote(int index

问题 I am reading Java Concurrency in Practice I am confused with the specific explanation regarding happens-before relationship. It states that, operations are ordered by a partial ordering called happens-before What exactly does this mean by "partial ordering" ? (There is an explanation in the book but its not clear to me ) 回答1: Partial Ordering means that not every pair of operations has the relation happens-before . Actually, the fact that not every pair of operations has that relation enables

问题 Given a class A with variable x. Variable x is set in class constructor: A() { x = 77; } We want to publish x to some other thread. Consider the following 3 cases of variable x thread-safe (?) publication: 1) x is final 2) x is volatile 3) x is set in synchronized block synchronized(someLock) { A a = new A(); a.x = 77; } Thread2 simply prints x: System.out.println(a.x); The question is: is it possible to observe '0' printed by Thread2? Or it is guaranteed by JMM that '77' will be printed or

问题 Some background I'm working on building a programming language for digital media programming, which should support concurrency using no-sharing message passing and soft real-time (i.e. do your best to compute audio/video without losing samples or frames and with a constant throughput). It turns out that both these features are surprisingly difficult to combine, mainly because of one particular constraint: real-time code should not dynamically allocate memory. My language should make it easy

问题 I've written a read-write lock using Python's concurrency primitives (I think!). Every implementation I've read on SO or elsewhere seems to use 2 locks -- one for reads, and another for writes. My implementation contains only one monitor for reads, but I may be missing something crucial -- can anyone confirm that this will work? If so, what is the benefit to using an additional write lock? This is the classic read-write lock with preference for readers (may starve writers). I use a dummy

问题 I've written a read-write lock using Python's concurrency primitives (I think!). Every implementation I've read on SO or elsewhere seems to use 2 locks -- one for reads, and another for writes. My implementation contains only one monitor for reads, but I may be missing something crucial -- can anyone confirm that this will work? If so, what is the benefit to using an additional write lock? This is the classic read-write lock with preference for readers (may starve writers). I use a dummy

问题 I just have a problem relative to concurrency whose logic flow is when a client (called Oracle Forms) will submit a request （called concurrent program ) and call a plsql procedure, this procedure eventually will call a java static method. What I find is that when I submit two request in the same time or in a very short interval(like 1 second), some concurrency problem will be noticed. The java method is the start point of doing something that search from the database suggest that which