ScalaPegasusAsyncTable

ScalaPegasusAsyncTable接口提供的方法均为异步API，封装了java client的异步接口。对应API功能可参考ScalaPegasusClient接口和Java客户端文档#pegasusTableInterface，接口封装形式如：

@throws[PException]    def multiGetH, S            (implicit hSer: SER[H], sSer: SER[S]): Future[MultiGetResult[S, Array[Byte]]] = {        val result = table.asyncMultiGet(hashKey, sortKeys, maxFetchCount, maxFetchSize, timeout)        toScala(result)(convertMultiGetResult[S])    }

其中table.asyncMultiGet(hashKey, sortKeys, maxFetchCount, maxFetchSize, timeout)即Java client接口，参数传递原理参见实现原理，toScala(result)(convertMultiGetResult[S])的完整形式如下：

implicit private [scalaclient] def toScala[A, B](future: NFuture[A])(implicit f: A => B): Future[B] = {
        val promise = Promise[B]()
        future.addListener(new GenericFutureListener[NFuture[_ >: A]] {
            override def operationComplete(future: NFuture[_ >: A]): Unit = {
                if (future.isSuccess) {
                    promise.success(f(future.get.asInstanceOf[A]))
                } else {
                    promise.failure(future.cause())
                }
            }
        })
        promise.future
    }

使用隐式转换实现Java的异步编程到Scala的异步编程变换，该函数利用io.netty.util.concurrent.{GenericFutureListener, Future => NFuture}实现异步编程