def prepareConf()

in server/src/main/scala/org/apache/livy/sessions/Session.scala [54:102]
43 lines of code
7 McCabe index (conditional complexity)

  def prepareConf(
      conf: Map[String, String],
      jars: Seq[String],
      files: Seq[String],
      archives: Seq[String],
      pyFiles: Seq[String],
      livyConf: LivyConf): Map[String, String] = {
    if (conf == null) {
      return Map()
    }

    val errors = if (livyConf.getBoolean(LivyConf.SESSION_ALLOW_CUSTOM_CLASSPATH)) {
      conf.keySet.filter(configBlackList.contains)
    } else {
      conf.keySet.filter((configBlackList ++ BLACKLIST_CUSTOM_CLASSPATH).contains)
    }
    if (errors.nonEmpty) {
      throw new IllegalArgumentException(
        "Blacklisted configuration values in session config: " + errors.mkString(", "))
    }

    val confLists: Map[String, Seq[String]] = livyConf.sparkFileLists
      .map { key => (key -> Nil) }.toMap

    val userLists = confLists ++ Map(
      LivyConf.SPARK_JARS -> jars,
      LivyConf.SPARK_FILES -> files,
      LivyConf.SPARK_ARCHIVES -> archives,
      LivyConf.SPARK_PY_FILES -> pyFiles)

    val merged = userLists.flatMap { case (key, list) =>
      val confList = conf.get(key)
        .map { list =>
          resolveURIs(list.split("[, ]+").toSeq, livyConf)
        }
        .getOrElse(Nil)
      val userList = resolveURIs(list, livyConf)
      if (confList.nonEmpty || userList.nonEmpty) {
        Some(key -> (userList ++ confList).mkString(","))
      } else {
        None
      }
    }

    val masterConfList = Map(LivyConf.SPARK_MASTER -> livyConf.sparkMaster()) ++
      livyConf.sparkDeployMode().map(LivyConf.SPARK_DEPLOY_MODE -> _).toMap

    conf ++ masterConfList ++ merged
  }