scala学习笔记(十四):fluent style(流式风格代码)

阅读更多

     我们在使用spark的时候 开头经常写这样的fluent style代码

 val conf = new SparkConf().setAppName("ParallelizeCollection").setMaster("local")

    那我们自己怎样然我们自己的代码能实现这样的效果，其实想要使用流式风格

    1、如果你的类会被继承的话 方法返回类型必须是this.type 

    2、如果你的类不会被继承的话 方法return是this就可以

  

object FluentStyleScala  {
  def main(args: Array[String]): Unit = {
    /**
     * A fluent style of programming lets users of your API write code by chaining method calls together
     * 想要使用流式风格 1、如果你的类会被继承的话 方法返回类型必须是this.type  2、如果你的类不会被继承的话 方法return是this就可以
     */
    val e = new Worker().setAge(10).setName("jian").setRole("Developer")
    println(e)
    
    val p = new Pizza()
      .setCrustSize(14)
     .setCrustType("thin")
     .addTopping("cheese")
     .addTopping("green olives")
     .print()
  }
}

class Emplory{
  protected var name = None:Option[String]
  protected var age = None:Option[Int]
  
  def setName(name:String):this.type = {
    this.name = Some(name)
    this
  }
  
  def setAge(age:Int):this.type = {
    this.age = Some(age)
    this
  }
  
  override def toString() = s"[name] = $name [age] = $age"
}

class Worker extends Emplory{
  protected var role = ""
  def setRole(role: String): this.type = {
      this.role = role
      this
  }
  override def toString = {
      "%s, %d, %s".format(name.get, age.get, role)
  }
}

final class Pizza{
  import scala.collection.mutable.ArrayBuffer
    private val toppings = ArrayBuffer[String]()
    private var crustSize = 0
    private var crustType = ""
    def addTopping(topping: String) = {
        toppings += topping
        this
    }
    def setCrustSize(crustSize: Int) = {
        this.crustSize = crustSize
        this
    }
    def setCrustType(crustType: String) = {
        this.crustType = crustType
        this
    }
    def print() {
        println(s"crust size: $crustSize")
        println(s"crust type: $crustType")
        println(s"toppings: $toppings")
    }
}