我對 Java 并發(fā)非常陌生，并且在嘗試使用鎖和監(jiān)視器編寫玩具問題時陷入困境。問題的要點是，我有一個具有g(shù)et和put方法的類，并且本質(zhì)上是線程消費和生產(chǎn)的容器。對于我的生活，我無法正確同步，最終會出現(xiàn)死鎖或IllegalMonitorStateException.package concurrencyobject ThreadsMain extends App { val syncVar = new SyncVar[Int]() val producer = new Thread { override def run(): Unit = { for (x <- 1 to 15) { syncVar.synchronized { if (!syncVar.isEmpty) { syncVar.wait() } else { syncVar.put(x) syncVar.notify() } } } } } producer.run() val consumer = new Thread { this.setDaemon(true) override def run(): Unit = { while (true) { syncVar.synchronized { if (syncVar.isEmpty) { syncVar.wait() } else { println(syncVar.get()) syncVar.notify() } } } } } consumer.run() producer.join() consumer.join()}class SyncVar[T]() { var isEmpty: Boolean = true var value: Option[T] = None def get(): T = { if (isEmpty) throw new Exception("Get from empty SyncVar") else { val toReturn = value.get value = None isEmpty = true toReturn } } def put(x: T): Unit = { if (!isEmpty) throw new Exception("Put on non-empty SyncVar") else { value = Some(x) isEmpty = false } }}
1 回答
隔江千里
TA貢獻1906條經(jīng)驗 獲得超10個贊
有幾個問題：
你應(yīng)該使用
starton notrun。如果您正在使用
join，則將踏面設(shè)置為守護線程是沒有意義的。當(dāng)您
if ... else在生產(chǎn)商中進行操作時，您只會得到奇數(shù)。它應(yīng)該只是if和其余的if（實際上while是一個更好的做法）。
我認為這樣代碼可以滿足您的需求：
object ThreadsMain extends App {
val syncVar = new SyncVar[Int]()
val isDone = new AtomicBoolean(false)
val producer = new Thread {
override def run(): Unit = {
for (x <- 1 to 15) {
syncVar.synchronized {
while (!syncVar.isEmpty) {
syncVar.wait()
}
syncVar.put(x)
syncVar.notify()
}
}
isDone.set(true)
}
}
producer.start()
val consumer = new Thread {
override def run(): Unit = {
while (!isDone.get()) {
syncVar.synchronized {
while (syncVar.isEmpty) {
syncVar.wait()
}
println(syncVar.get())
syncVar.notify()
}
}
}
}
consumer.start()
producer.join()
consumer.join()
}
class SyncVar[T]() {
var isEmpty: Boolean = true
var value: Option[T] = None
def get(): T = {
if (isEmpty) throw new Exception("Get from empty SyncVar")
else {
val toReturn = value.get
value = None
isEmpty = true
toReturn
}
}
def put(x: T): Unit = {
if (!isEmpty) throw new Exception("Put on non-empty SyncVar")
else {
value = Some(x)
isEmpty = false
}
}
}
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