How to convert a immutable scala list to a mutable java list

[Richard Grossman]

Hi

My problem seems to be an easy (may he is) but I can't find how to resolve without changing all my immutable list to mutable

I've a scala application using some sealed part of a java application

In my code I get something like

  def filterAdList(fromChain: ChainMessage, adList: List[Pair[IAdEngineFactory, AdOrParams]]): ListHttpResult = {

    val listOfAd = adList flatMap (pair => {

      val targetingContext = fromChain.engineContext.createTargetingContext(pair.getLeft)

      targetingContext.adRetrieved = pair.getRight.getAd

      targetingContext.retriever = pair.getLeft.createAdRetriever()

      chainFinalizeTargeting.executeChain(targetingContext)

      if (targetingContext.getAdContext.ad == null) None

      else Some(targetingContext.getAdContext.ad)

    })

    if (listOfAd.isEmpty) ListHttpResult(fromChain, None)

    else ListHttpResult(fromChain, Some(listOfAd.toList))

  }

Ok simple here I get a immutable list from listOfAd.toList

Now I convert it to java list simple

  import collection.JavaConverters._

  chain.engineContext.adList = listResult.get.asJava

The problem is java code that try now to sort this map like this

  Collections.sort(adList, new Comparator<Pair<IAdEngineFactory, AdOrParams>>() {

                @Override

                public int compare(Pair<IAdEngineFactory, AdOrParams> o1, Pair<IAdEngineFactory, AdOrParams> o2) {

                    if (o1.getRight() != null && o2.getRight() != null) {

                        if (o1.getRight().getAd().getPricing() < o2.getRight().getAd().getPricing()) return 1;

                        else if (o1.getRight().getAd().getPricing() > o2.getRight().getAd().getPricing()) return -1;

                    }

                    return 0;

                }

            });

get always 

java.lang.UnsupportedOperationException: null

at java.util.AbstractList.set(AbstractList.java:115) ~[na:1.6.0_45]

at java.util.AbstractList$ListItr.set(AbstractList.java:412) ~[na:1.6.0_45]

at java.util.Collections.sort(Collections.java:161) ~[na:1.6.0_45]

at com.inneractive.chains.fetch.EvaluateWinRTBHandler.findSecondAuctionPrice(EvaluateWinRTBHandler.java:78) ~[chains-2.1.20-SNAPSHOT.jar:na]

at com.inneractive.chains.fetch.EvaluateWinRTBHandler.process(EvaluateWinRTBHandler.java:33) ~[chains-2.1.20-SNAPSHOT.jar:na]

at com.inneractive.bootstraps.AdRequestBootstraps$$anonfun$receive$1.applyOrElse(AdRequestBootstraps.scala:45) ~[AdRequestBootstraps$$anonfun$receive$1.class:na]

at akka.actor.ActorCell.receiveMessage(ActorCell.scala:425) [akka-actor_2.10-2.1.4.jar:na]

at akka.actor.ActorCell.invoke(ActorCell.scala:386) [akka-actor_2.10-2.1.4.jar:na]

at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:230) [akka-actor_2.10-2.1.4.jar:na]

at akka.dispatch.Mailbox.run(Mailbox.scala:212) [akka-actor_2.10-2.1.4.jar:na]

at akka.dispatch.ForkJoinExecutorConfigurator$MailboxExecutionTask.exec(AbstractDispatcher.scala:506) [akka-actor_2.10-2.1.4.jar:na]

at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:262) [scala-library-2.10.1.jar:na]

at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:975) [scala-library-2.10.1.jar:na]

at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1478) [scala-library-2.10.1.jar:na]

at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:104) [scala-library-2.10.1.jar:na]

I think i get this because of the immutability of the scala list

may be I wrong, please help

Thanks

[Bob Hiestand]

Richard,

Does this work?

  import collection.JavaConverters._

  chain.engineContext.adList = listResult.get.to[scala.collection.mutable.ListBuffer].asJava

Thank you,

Bob

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[Richard Grossman]

Yes working 

Thanks