Find the thread by name and change its priority

gistfile1.scala

  // ...
    val connection = factory.newConnection()
    changeInnerPriority(connection,
      config.get[Int]("tq.connectionPriority").getOrElse(Thread.NORM_PRIORITY))
  // ...

  def changeInnerPriority(connection: com.rabbitmq.client.Connection,
                     priority: Int): Unit = {
    def getHostAddressAsString: String = {
      connection.getAddress.getHostAddress
    }
    // change priority of the thread to reduce CPU load
    // caused by the infinite loop inside the connection:
    // TODO [nick] do this hardcoded address is stable enough?
    val hostAddress = getHostAddressAsString
    val threadName = "AMQP Connection " + hostAddress + ":" + connection.getPort
    getThreadByName(threadName) match {
      case Some(th) => th.setPriority(priority)
      case None => ()
    }
  }

  def getThreadByName(name: String): Option[Thread] = {
    getAllThreads.find(th => th.getName == name)
  }

  def getAllThreads: Array[Thread] = {
    val rootGroup = rootThreadGroup
    var threads: Array[Thread] = new Array[Thread](rootGroup.activeCount)
    // we call enumerate() repeatedly until the array is large enough to
    // contain all entries, since activeCount does not guarantee to supply us
    // the exact number
    while (rootGroup.enumerate(threads, true) == threads.length) {
      threads = new Array[Thread](threads.length * 2)
    }
    threads
  }

  def rootThreadGroup: ThreadGroup = {
    var rootGroup: ThreadGroup = Thread.currentThread().getThreadGroup
    // go upstairs until we get the root
    var parentGroup: ThreadGroup = rootGroup
    while (parentGroup != null) {
      rootGroup = parentGroup
      parentGroup = rootGroup.getParent
    }
    rootGroup
  }