Untitled

Problems with appending objects to a ListBuffer in Scala
// get the references and ensure that it are rally ListBuffers / Lists
val handCards: mutable.ListBuffer[ClientCard] = playerPanel.player.handCards
val chosenCards: List[ClientCard] = _chosenCards

// print the number of elements per list
println("number of hand cards: " + handCards.size)
println("number of chosen cards: " + chosenCards.size)

// append the chosen cards to the hand cards
println("append operation: " + handCards + " ++= " + chosenCards)
handCards ++= chosenCards

// print the number of hand cards again
println("number of hand cards: " + handCards.size)

number of hand cards: 5
number of chosen cards: 2

append operation: ListBuffer(
    rftg.card.Card$$anon$1@1304043,
    rftg.card.Card$$anon$1@cb07ef,
    rftg.card.Card$$anon$1@176086d,
    rftg.card.Card$$anon$1@234265,
    rftg.card.Card$$anon$1@dc1f04
) ++= List(
    rftg.card.Card$$anon$1@1784427,
    rftg.card.Card$$anon$1@c272bc
)

number of hand cards: 5

trait ClientCard extends AnyRef with ClientObject with CardLike

trait ClientObject extends Serializable {
    def uid: Int
}

trait CardLike {
    val imagePath: String
}

def clientCard = new ClientCard() {
    val uid = Card.this.hashCode()
    val imagePath = CardTemplate.cardFolder + Card.this.imageFilename
}

// definition of ClientPlayer trait
trait ClientPlayer extends ClientObject {
    val victoryPoints: Int
    val handCards: mutable.ListBuffer[ClientCard]
    val playedCards: mutable.ListBuffer[ClientCard]
}

// piece of code to create a client player
def clientPlayer = new ClientPlayer() {
    val uid = Player.this.hashCode()
    val victoryPoints = Player.this.victoryPoints

    val handCards = new mutable.ListBuffer[ClientCard]
    handCards ++= (Player.this.handCards.map(_.clientCard))

    val playedCards = new mutable.ListBuffer[ClientCard]
    playedCards ++= Player.this.playedCards.map(_.clientCard)
}

import collection.mutable.ListBuffer
import java.io._
val baos = new ByteArrayOutputStream
val oos = new ObjectOutputStream(baos)
oos.writeObject( ListBuffer(1,2,3) )
val bais = new ByteArrayInputStream( baos.toByteArray )
val ois = new ObjectInputStream(bais)
val lb = ois.readObject.asInstanceOf[ListBuffer[Int]]
val lb2 = ListBuffer[Int]() ++= lb
lb2 ++= List(1)  // All okay
lb ++= List(1)  // Throws an exception for me