Scala面向?qū)ο髲氐拙癝park源碼閱讀

不用寫public class中的public

class Person {
     private var myName = "flink"
     def name = this.myName
     def name_=(newName:String){ //重載?
  myName = newName
     println("Hi " + this.myName)
     }
}

class Person {
     private var myName = "flink"
     def name = this.myName
     def update(newName : String){
  myName = newName
     println("Hi " + this.myName)
     }
}

重要：private[this]
//對(duì)象私有,不能被其他對(duì)象訪問

class Person {
     private var myName = "flink"
     def name = this.myName
     def update(newName : String){
  myName = newName
     println("Hi " + this.myName)
     }
  def talk(p:Person) = {
  println("Hello "+ p.name)
  }
}

scala> val p1 = new Person
p1: Person = Person@13cd7ea5

scala> val p2 = new Person
p2: Person = Person@c4c0b41

scala> p2.update("Spark")
Hi Spark

scala> p1.talk(p2)
Hello Spark

scala> p2.talk(p1)
Hello flink

class Person {
     private[this] var Name = "flink"

     def update(newName : String){
     println("Hi ")
     }
  def talk(p:Person) = {
  println("Hello "+ p.name)
  }
}
<console>:14: error: value name is not a member of Person
       println("Hello! " + p.name)
                             ^
//不能被其他對(duì)象訪問。

//重載構(gòu)造器
//默認(rèn)構(gòu)造器在類定義內(nèi)，任何非def的都將執(zhí)行

class Person {
    var name = "flink"
    var age = 10

     def update(newName : String){
     println("Hi ")
     }
 def this(name: String){
 this()//必須調(diào)用一個(gè)其他構(gòu)造器
 this.name = name
 }
 def this(name: String, age:Int){
 this(name)//必須調(diào)用一個(gè)其他構(gòu)造器
 this.age = age
 }
}
//Scala 的內(nèi)部類的不同內(nèi)部類為不同類型

object
定義類后同時(shí)定義object存放靜態(tài)成員和方法，為伴生對(duì)象，它的構(gòu)造器不接受參數(shù)，只在第一次調(diào)用執(zhí)行一次

object Person {
var salary = 0.0
println("Scala")
def getSalary = salary
}

apply是當(dāng)前類的對(duì)象的工廠方法

程序入口在object內(nèi)的main方法def main(argStrings:Array[String]) {}

抽象類

重寫父類要加override，重寫父類的抽象方法必須加override關(guān)鍵字

抽象屬性，不給值，需要覆蓋

trait？接口？

DAGScheduler 是一個(gè)至關(guān)重要的類