val nodes = Array.fill[mutable.Buffer[Int]](numNodes){new ArrayBuffer[Int]() with mutable.SynchronizedBuffer[Int]}
def addMutualEdge(i: Int)(j: Int) {nodes(i) += j; nodes(j) += i}
当我编译这个时，我收到弃用警告：
SynchronizedBuffer is deprecated. Synchronization via traits is deprecated as it is inherently reliable. Consider java.util.concurrent.ConcurrentLinkedQueue as an alternative
如何在上面的代码中使用 java 库？
您可以只使用ConcurrentLinkedQueue，而不是Buffer因为它也是可变的：
scala> import java.util.concurrent._
import java.util.concurrent._
scala> val nodes = Array.fill(10){new ConcurrentLinkedQueue[Int]()}
nodes: Array[java.util.concurrent.ConcurrentLinkedQueue[Int]] = Array([], [], [], [], [], [], [], [], [], [])
scala> def addMutualEdge(i: Int)(j: Int) {nodes(i).add(j); nodes(j).add(i)}
addMutualEdge: (i: Int)(j: Int)Unit
这是最快的选择，因为此队列基于 CAS 操作，因此没有阻塞（与 相比SynchronizedBuffer）。另一种选择是直接同步操作：
scala> val nodes = Array.fill[mutable.Buffer[Int]](10){new ArrayBuffer[Int]()}
nodes: Array[scala.collection.mutable.Buffer[Int]] = Array(ArrayBuffer(), ArrayBuffer(), ArrayBuffer(), ArrayBuffer(), ArrayBuffer(), ArrayBuffer(), ArrayBuffer(), ArrayBuffer(), ArrayBuffer(), ArrayBuffer())
scala> def addMutualEdge(i: Int)(j: Int) = this.synchronized{nodes(i) += j; nodes(j) += i}
addMutualEdge: (i: Int)(j: Int)scala.collection.mutable.Buffer[Int]
您还可以Collections.synchronizedList(...)结合使用 javascala.collection.JavaConverters.asScala
import java.util._
import scala.collection.JavaConverters._
scala> val nodes = Array.fill(10){Collections.synchronizedList(new ArrayBuffer[Int]().asJava).asScala}
nodes: Array[scala.collection.mutable.Buffer[Int]] = Array(Buffer(), Buffer(), Buffer(), Buffer(), Buffer(), Buffer(), Buffer(), Buffer(), Buffer(), Buffer())
或者您可以使用AtomicReferenceArray：
implicit class RichAtomic[T](a: AtomicReferenceArray[List[T]]) { def apply(i: Int) = (a,i); def update(i: Int, e: List[T]) = a.set(i, e)}
implicit class RichList[T](a: (AtomicReferenceArray[List[T]], Int)) { def ::=(e: T) = while({val lst = a._1.get(a._2);!a._1.compareAndSet(a._2, lst, e :: lst)}){}}
implicit def toList[T](a: (AtomicReferenceArray[List[T]], Int)) = a._1.get(a._2)
val nodes = new AtomicReferenceArray(Array.fill[List[Int]](10){Nil})
scala> def addMutualEdge(i: Int)(j: Int) = {nodes(i) ::= j; nodes(j) ::= i}
addMutualEdge: (i: Int)(j: Int)Unit
用于提供与 just 类似的接口的隐式Array。请注意，这::=会将元素添加到列表的开头。