weakhashmap.scala

来自「JAVA 语言的函数式编程扩展」· SCALA 代码 · 共 32 行

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2006-2008, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://www.scala-lang.org/           **
** /____/\___/_/ |_/____/_/ | |                                         **
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// $Id: WeakHashMap.scala 14016 2008-02-15 11:30:27Z michelou $

package scala.collection.jcl

/** <p>
 *    A map that is backed by a Java weak hash map, whose keys are maintained
 *    as weak references.
 *  </p>
 *  <p>
 *    Because keys are weak references, the garbage collector can collect
 *    them if they are not referred to elsewhere.
 *  </p>
 *  <p>
 *    Useful for implementing caches.
 *  </p>
 *
 *  @author Sean McDirmid
 */
class WeakHashMap[K, E](override val underlying: java.util.WeakHashMap[K, E]) extends MapWrapper[K, E] {
  def this() = this(new java.util.WeakHashMap[K, E])
  override def clone: WeakHashMap[K, E] =
    throw new CloneNotSupportedException("The underlying map doesn't implement the Cloneable interface")
}