如何在akka中扩展超级演员的行为

Posted 2023-04-18

【中文标题】如何在akka中扩展超级演员的行为

【英文标题】：How extend behaviour of super actor in akka

【发布时间】：2017-09-29 07:29:28

【问题描述】：

我想使用 akka actor 实现 CRUD 操作。我是akka新手，所以不知道akka actor的设计基础。

我想在多个子actor中分享akkaactor的行为。

我想保存和删除学生、教师和其他实体的示例。

我为 StudentDao.scala 创建了actor

class StudentDao extends Actor with ActorLogging

 override def Receive = 

    case Add(student) =>
      // Add to database
    case Delete =>
      //Delete from database     
   // Some other cases related to Student entity
  

case object StudentDao
  case class Add(user : Student)
  case class Delete(id : String)

我也有 TeacherDao.scala 的演员

class TeacherDao extends Actor with ActorLogging

 override def Receive = 

    case Add(teacher) =>
      // Add to database
    case Delete =>
      //Delete from database      
    // Some other cases related to teacher entity

  
 

object TeacherDao
  case class Add(user : teacher)
  case class Delete(id : String)

我想为两个 dao 抽象删除方法。 所以我创建了 BaseDao.scala

class BaseDao extends Actor with ActorLogging

  override def Receive = 

    case Delete =>
      //Delete from database   dao.delete
  

如何使用基本actor进行抽象。

【参考方案1】：

orElse 是扩展actor 行为的方式，因为actor 的Receive 只是PartialFunction[Any, Unit] 的别名。下面是您的用例的具体说明。

首先，在必须与参与者混合的特征中定义基本行为。为避免重复，请将 Delete 案例类移动到此 trait 的伴随对象中。

trait BaseDao  this: Actor with ActorLogging =>
  import BaseDao._

  def baseBehavior: Receive = 
    case Delete(id) =>
      log.info(s"Deleting $id from db")
      // delete from db
  


object BaseDao 
  case class Delete(id: String)

然后，将上述特征混合到您的其他参与者中，并将这些行为与orElse 链接起来。请注意，我创建了虚拟 Student 和 Teacher 案例类，以便可以编译此代码。 StudentDao:

class StudentDao extends Actor with ActorLogging with BaseDao 
  import StudentDao._

  def studentBehavior: Receive = 
    case Add(student) =>
      log.info(s"Adding student: $student")
    // some other cases related to Student
  

  def receive = studentBehavior orElse baseBehavior


object StudentDao 
  case class Add(user: Student)

case class Student(name: String)

还有TeacherDao:

class TeacherDao extends Actor with ActorLogging with BaseDao 
  import TeacherDao._

  def teacherBehavior: Receive = 
    case Add(teacher) =>
      log.info(s"Adding teacher: $teacher")
    // some other cases related to Teacher
  

  def receive = teacherBehavior orElse baseBehavior


object TeacherDao 
  case class Add(user: Teacher)

case class Teacher(name: String)

【参考方案2】：

您可以为基础actor创建一个特征，使用一个公共接收函数orElse另一个必须在子actor中实现的函数：

trait BaseActor extends Actor 

  override def receive: Receive = commonReceive orElse handleReceive

  def commonReceive: Receive = 
    case CommonMessage => // do something
  

  def handleReceive: Receive

然后你的子actor只需要实现handleReceive：

class SubActor extends BaseActor 

  override def handleReceive: Receive = 
    case SpecificMessage => // do something