emesday

  protected def typeToTypeTag[T](tpe: Type): TypeTag[T] = {
    TypeTag(currentMirror, new TypeCreator {
      override def apply[U <: Universe with Singleton](m: api.Mirror[U]): U#Type = {
        tpe.asInstanceOf[U#Type]
      }
    })
  }

  protected def typeToClassTag[T](tpe: Type): ClassTag[T] = typeTagToClassTag(typeToTypeTag(tpe))

emesday

  def topByKey(key: String, orderBy: String, n: Int): DataFrame = {
    val keyIndex = df.schema.fieldIndex(key)
    val orderByIndex = df.schema.fieldIndex(orderBy)
    val ord = df.schema.fields(orderByIndex).dataType match {
      case o: StringType => Ordering.by[Row, String](_.getString(orderByIndex))
      case o: IntegerType => Ordering.by[Row, Int](_.getInt(orderByIndex))
      case o: LongType => Ordering.by[Row, Long](_.getLong(orderByIndex))
      case o: FloatType => Ordering.by[Row, Float](_.getFloat(orderByIndex))
      case o: DoubleType => Ordering.by[Row, Double](_.getDouble(orderByIndex))
      case _ => throw new IllegalArgumentException

emesday

package w20160827

case class Log(s: String, l: Long, f: String, t: String, p: String) {

  def usingFixedSize: String = {
    // 23 = Long.MaxValue.toString.length + ("\t" * 4).length
    val size = 23 + s.length + f.length + t.length + p.length
    val sb = new StringBuilder(size, s)
    sb append "\t"; sb append l
    sb append "\t"; sb append f