SavingsBankAccount程序中Scala演员的用例

Question

这不是任何形式的任务。 我正在学习学习Scala和Scala并发性，最好是与Akka Actors一起学习。 我执行此操作的方法之一是提出一些简单的程序设计，然后尝试提出一个涉及将Actor /并发应用于设计的实现：

我要编写的程序是具有输入部分和输出部分的储蓄银行帐户应用程序。
XYZ银行向客户提供开设储蓄账户的计划
1）客户ABC在开户时被要求提供其个人详细信息
2）客户可以将资金存入他/她的帐户
3）客户可以从他/她的帐户中提取资金
4）如果帐户余额低于$ 100，则通知客户。 （例如，当客户从应用程序的输入屏幕中选择选项3时，系统将通知他/她当时的帐户余额低于$ 100，因此除非有更多的存款，否则提款是不可能的。）
5）应用程序应该能够维护客户的交易历史记录并显示交易记录历史记录（例如：当应用程序显示输入屏幕时，其中一个选项是-显示交易记录历史记录。当使用数字选择此选项时，提示，应用程序应显示余额）
程序的输入部分包含4个选项，这些选项在命令行中显示：1.创建帐户2.存钱3.提取钱。 4.显示交易记录

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现在，我现在要完成的工作是理解和识别：
1）在这样的程序中，Akka actor / Scala并发库的用例是什么？ 如果有此应用程序中的并发角色，该怎么办？
我可以最好地利用哪些Scala集合库？

Answer 1

我希望这可以解决问题： http : //alexminnaar.com/introduction-to-the-multithreading-problem-and-the-akka-actor-solution.html

注意：我只是注意到这篇文章很旧。 我将在2018年发布答案。

Update1 ：（在注释中提到后，从链接进行解释）

这是多种可能策略中的一种。

有两个演员

1. BankAccount-管理余额

     object WireTransfer { case class Transfer(from: ActorRef, to: ActorRef, amount: BigInt) case object Done case object Failed } //actor implementing the actions of a wire transfer between two bank account actors class WireTransfer extends Actor { import WireTransfer._ def receive = LoggingReceive { //If Transfer message is received, send withdraw message to 'from' and wait for reply case Transfer(from, to, amount) => from ! BankAccount.Withdraw(amount) context.become(awaitFrom(to, amount, sender)) } //If Withdraw was successful, send deposit to other bank account actor, or else give them a failure message def awaitFrom(to: ActorRef, amount: BigInt, customer: ActorRef): Receive = LoggingReceive { case BankAccount.Done => to ! BankAccount.Deposit(amount) context.become(awaitTo(customer)) case BankAccount.Failed => customer ! Failed context.stop(self) } //If deposit was successful, send 'Done' to original actor that sent Transfer message def awaitTo(customer: ActorRef): Receive = LoggingReceive { case BankAccount.Done => customer ! Done context.stop(self) } } 

2. WireTransfer-将余额从一个帐户转移到另一个帐户。

     object WireTransfer { case class Transfer(from: ActorRef, to: ActorRef, amount: BigInt) case object Done case object Failed } //actor implementing the actions of a wire transfer between two bank account actors class WireTransfer extends Actor { import WireTransfer._ def receive = LoggingReceive { //If Transfer message is received, send withdraw message to 'from' and wait for reply case Transfer(from, to, amount) => from ! BankAccount.Withdraw(amount) context.become(awaitFrom(to, amount, sender)) } //If Withdraw was successful, send deposit to other bank account actor, or else give them a failure message def awaitFrom(to: ActorRef, amount: BigInt, customer: ActorRef): Receive = LoggingReceive { case BankAccount.Done => to ! BankAccount.Deposit(amount) context.become(awaitTo(customer)) case BankAccount.Failed => customer ! Failed context.stop(self) } //If deposit was successful, send 'Done' to original actor that sent Transfer message def awaitTo(customer: ActorRef): Receive = LoggingReceive { case BankAccount.Done => customer ! Done context.stop(self) } }