概述

scala泛型结合隐式转换使用

实践

代码

package com.fun.scala

/**
 * 视图界定
 */
object Genericity04 {
  def main(args: Array[String]): Unit = {
    val s1 = new Stu("test", 33)
    val s2 = new Stu("test2", 32)
    println(new MaxValue2(s1, s2).compare)

    // 隐式转换与泛型结合
    implicit def stu2Ordered(stu: Stu2) = new Ordered[Stu2] {
      override def compare(that: Stu2): Int = stu.age - that.age
    }

    val s3 = new Stu2("test", 33)
    val s4 = new Stu2("test2", 34)
    println(new MaxValue2(s3, s4).compare)

  }

  // <% 视图界定 int2Integer
  class MaxValue2[T <% Comparable[T]](a: T, b: T) {
    def compare = if (a.compareTo(b) > 0) a else b
  }

  // Ordered 使用的是 Comparable
  class MaxValueOrdered[T <% Ordered[T]](a: T, b: T) {
    def compare = if (a.compareTo(b) > 0) a else b
  }

}

class Stu(val name: String, val age: Int) extends Ordered[Stu] {
  override def compare(that: Stu): Int = this.age - that.age

  override def toString: String = this.name + "\t" + this.age
}

class Stu2(val name: String, val age: Int) {
  override def toString: String = this.name + "\t" + this.age
}

执行

结束

scala泛型结合隐式转换使用 至此结束。