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/*
 * Scala (https://www.scala-lang.org)
 *
 * Copyright EPFL and Lightbend, Inc.
 *
 * Licensed under Apache License 2.0
 * (http://www.apache.org/licenses/LICENSE-2.0).
 *
 * See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.
 */

package scala.tools.nsc.backend.jvm.opt

import scala.collection.mutable.Map
import scala.jdk.CollectionConverters._
import java.util.{LinkedHashMap, Collections, Map => JMap}

object LruMap{
  def apply[K,V](maxSize:Int, threadsafe:Boolean): Map[K,V] = {
    require (maxSize > 0)
    val basic = new LruMapImpl[K,V](maxSize)
    val threaded = if (threadsafe) Collections.synchronizedMap(basic) else basic

    threaded.asScala
  }

  private class LruMapImpl[K,V](maxSize: Int) extends LinkedHashMap[K,V] {
    override def removeEldestEntry(eldest: JMap.Entry[K, V]): Boolean = {
      size() > maxSize
    }
  }
}