2.3.3 工具类: RadomOptions

按照一定的分布生成随机选项的工具类

package com.atguigu.dw.gmall.mock.util

import scala.collection.mutable.ListBuffer

/**
  * 根据提供的值和比重, 来创建RandomOptions对象.
  * 然后可以通过getRandomOption来获取一个随机的预定义的值
  */
object RandomOptions {
    def apply[T](opts: (T, Int)*) = {
        val randomOptions = new RandomOptions[T]()
        randomOptions.totalWeight = (0 /: opts) (_ + _._2) // 计算出来总的比重
        opts.foreach {
            case (value, weight) => randomOptions.options ++= (1 to weight).map(_ => value)
        }
        randomOptions
    }
}

class RandomOptions[T] {
    var totalWeight: Int = _
    var options = ListBuffer[T]()

    /**
      * 获取随机的 Option 的值
      *
      * @return
      */
    def getRandomOption() = {
        options(RandomNumUtil.randomInt(0, totalWeight - 1))
    }
}