gistfile1.scala

case class Node {
  val connections: ListBuffer[Connection] = new ListBuffer[Connection]
}

case class Connection(
  from: Node,
  val to: Node,
  val cost: Int,
  private val directed: Boolean = true
) {
  from.connections += this
  if(!directed) to.connections += new Connection(to, from, cost, true)
}

class Graph {
  val nodes: ListBuffer[Node] = new ListBuffer[Node]
  def getConnections(node: Node): Option[List[Connection]] = {
    nodes.find(n => n == node) match {
      case Some(node) =>
        Some(node.connections.toList)
      case None =>
        None
    }
  }
}

object GraphTest1 extends App {
  val nodeA = new Node()
  val nodeB = new Node()

  val con: Connection = new Connection(nodeA, nodeB, 5)
}