private def checkCollectionBehaviors()

in connector/src/main/scala/com/datastax/spark/connector/writer/TableWriter.scala [349:402]
40 lines of code
8 McCabe index (conditional complexity)

  private def checkCollectionBehaviors(table: TableDef, columnRefs: IndexedSeq[ColumnRef]) {
    val tableCollectionColumns = table.columns.filter(cd => cd.isCollection)
    val tableCollectionColumnNames = tableCollectionColumns.map(_.columnName)
    val tableListColumnNames = tableCollectionColumns
      .map(c => (c.columnName, c.columnType))
      .collect { case (name, x: ListType[_]) => name }

    val tableMapColumnNames = tableCollectionColumns
      .map(c => (c.columnName, c.columnType))
      .collect { case (name, x: MapType[_, _]) => name }

    val refsWithCollectionBehavior = columnRefs collect {
      case columnName: CollectionColumnName => columnName
    }

    val collectionBehaviorColumnNames = refsWithCollectionBehavior.map(_.columnName)

    //Check for non-collection columns with a collection Behavior
    val collectionBehaviorNormalColumn =
      collectionBehaviorColumnNames.toSet -- tableCollectionColumnNames.toSet

    if (collectionBehaviorNormalColumn.nonEmpty)
      throw new IllegalArgumentException(
        s"""Collection behaviors (add/remove/append/prepend) are only allowed on collection columns.
           |Normal Columns with illegal behavior: ${collectionBehaviorNormalColumn.mkString}"""
          .stripMargin
      )

    //Check that prepend is used only on lists
    val prependBehaviorColumnNames = refsWithCollectionBehavior
      .filter(_.collectionBehavior == CollectionPrepend)
      .map(_.columnName)
    val prependOnNonList = prependBehaviorColumnNames.toSet -- tableListColumnNames.toSet

    if (prependOnNonList.nonEmpty)
      throw new IllegalArgumentException(
        s"""The prepend collection behavior only applies to Lists. Prepend used on:
           |${prependOnNonList.mkString}""".stripMargin
      )

    //Check that remove is not used on Maps

    val removeBehaviorColumnNames = refsWithCollectionBehavior
      .filter(_.collectionBehavior == CollectionRemove)
      .map(_.columnName)

    val removeOnMap = removeBehaviorColumnNames.toSet & tableMapColumnNames.toSet

    if (removeOnMap.nonEmpty)
      throw new IllegalArgumentException(
        s"The remove operation is currently not supported for Maps. Remove used on: ${removeOnMap
          .mkString}"
      )
  }