什么是ev.R型?

我有一个结果集 com.datastax.driver.core.ResultSet 从中获取ExecutionInfo,从ExecutionInfo中提取queryTrace,如您所见,代码如下。

resultSet.getAllExecutionInfo.forEach { exeInfo: ExecutionInfo =>
        val queryTimeTaken: FiniteDuration = exeInfo.getQueryTrace.getDurationMicros.microsecond  //this works fine if i do getDurationMicros microsecond it return ev.R
        exeInfo.getQueryTrace.getEvents.forEach { event =>
          if (queryTimeTaken > timeTakenLimit) {
            TraceLogger.info {
              s"DateTime = ${sdf.format {event.getTimestamp}} Description = ${event.getDescription}  " +
                s"TimeElapsedMicro = ${event.getSourceElapsedMicros} Statement = ${exeInfo.getStatement}" +
                s" TimeTaken =$queryTimeTaken"
            }
          }
        }
      }

val queryTimeTaken:FiniteDuration=exeInfo.getQueryTrace.getDurationMicros.micros秒

getDurationMicros.microsecond 它返回FiniteDuration对象,但如果我返回 getDurationMicros microsecond 它回来了 ev.R 类型 有人能解释一下为什么它要重做这样的类型吗。这两条线的空间有什么不同?

它是否与后缀表达式求值有关?

编辑一个:

def a = 500
val x: FiniteDuration = a.microsecond // this works fine
val y: FiniteDuration = 500 microsecond

def a = 500
val x: ev.R = a.microsecond() // this gives ev.R
val y: FiniteDuration = 500 microsecond

def a = 500
val x: FiniteDuration  = a microsecond // this works fine
val y: FiniteDuration = 500 microsecond