From 070d598244f754cfa114b6dd4a8b35ea7159fc4d Mon Sep 17 00:00:00 2001
From: Martin Ring <martin.ring@encoway.de>
Date: Tue, 24 May 2022 10:25:01 +0200
Subject: [PATCH] add bank example
---
.gitignore | 7 +++
bank-actors/Account.scala | 32 ++++++++++++++
bank-actors/Bank.scala | 64 ++++++++++++++++++++++++++++
bank-actors/WireTransfer.scala | 37 ++++++++++++++++
bank-actors/build.sbt | 11 +++++
bank-actors/project/build.properties | 1 +
6 files changed, 152 insertions(+)
create mode 100644 .gitignore
create mode 100644 bank-actors/Account.scala
create mode 100644 bank-actors/Bank.scala
create mode 100644 bank-actors/WireTransfer.scala
create mode 100644 bank-actors/build.sbt
create mode 100644 bank-actors/project/build.properties
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2b5de01
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,7 @@
+.bloop
+.metals
+target
+project/project
+metals.sbt
+.bsp
+.vscode
\ No newline at end of file
diff --git a/bank-actors/Account.scala b/bank-actors/Account.scala
new file mode 100644
index 0000000..f915dab
--- /dev/null
+++ b/bank-actors/Account.scala
@@ -0,0 +1,32 @@
+import akka.actor.typed.ActorRef
+import akka.actor.typed.Behavior
+import akka.actor.typed.scaladsl.Behaviors
+
+object Account:
+ enum Message:
+ case GetBalance(sender: ActorRef[Balance])
+ case Deposit(amount: Int, client: ActorRef[MovementResponse])
+ case Withdraw(amount: Int, client: ActorRef[MovementResponse])
+
+
+
+ case class Balance(balance: Int)
+ enum MovementResponse:
+ case Ok
+ case NotOk
+
+ def behavior(number: Int, balance: Int): Behavior[Message] = Behaviors.receiveMessage {
+ case Message.GetBalance(sender) =>
+ sender ! Balance(balance)
+ Behaviors.same
+ case Message.Deposit(amount, client) =>
+ client ! MovementResponse.Ok
+ behavior(number,balance + amount)
+ case Message.Withdraw(amount, client) =>
+ if balance >= amount then
+ client ! MovementResponse.Ok
+ behavior(number,balance - amount)
+ else
+ client ! MovementResponse.NotOk
+ Behaviors.same
+ }
\ No newline at end of file
diff --git a/bank-actors/Bank.scala b/bank-actors/Bank.scala
new file mode 100644
index 0000000..7f40b1b
--- /dev/null
+++ b/bank-actors/Bank.scala
@@ -0,0 +1,64 @@
+import akka.actor.typed.ActorSystem
+import akka.actor.typed.{ActorRef,Behavior}
+import akka.actor.typed.scaladsl.Behaviors
+
+object Bank:
+ enum Message:
+ case CreateAccount(sender: ActorRef[Response.AccountCreated])
+ case AccountMessage(account: Int, msg: Account.Message)
+ case Transfer(from: Int, to: Int, amount: Int, client: ActorRef[Account.MovementResponse])
+
+ enum Response:
+ case AccountCreated(number: Int)
+
+ def behavior(accounts: Map[Int,ActorRef[Account.Message]]): Behavior[Message] = Behaviors.setup { context =>
+ Behaviors.receiveMessage {
+ case Message.CreateAccount(sender) =>
+ val number = accounts.size
+ val accountActor = context.spawn(Account.behavior(number, 0), s"account-$number")
+ sender ! Response.AccountCreated(number)
+ behavior(accounts + (number -> accountActor))
+ case Message.AccountMessage(account, msg) =>
+ accounts.get(account).foreach(_ ! msg)
+ Behaviors.same
+ case Message.Transfer(fromId,toId,amount,client) =>
+ val transferActor = for {
+ from <- accounts.get(fromId)
+ to <- accounts.get(toId)
+ } yield context.spawnAnonymous(WireTransfer.init(from,to,amount,client))
+ transferActor.getOrElse(client ! Account.MovementResponse.NotOk)
+ Behaviors.same
+ }
+ }
+
+
+
+@main def main =
+ val testBehavior = Behaviors.setup[Bank.Response | Account.Balance | Account.MovementResponse] { ctx =>
+ val bank = ctx.spawn(Bank.behavior(Map.empty), "bank")
+ bank ! Bank.Message.CreateAccount(ctx.self)
+ Behaviors.receiveMessage {
+ case Bank.Response.AccountCreated(x) =>
+ ctx.log.info(s"account $x was created")
+ bank ! Bank.Message.CreateAccount(ctx.self)
+ Behaviors.receiveMessage {
+ case Bank.Response.AccountCreated(y) =>
+ ctx.log.info(s"account $y was created")
+ bank ! Bank.Message.AccountMessage(x, Account.Message.Deposit(1000, ctx.self))
+ bank ! Bank.Message.AccountMessage(y, Account.Message.Withdraw(500, ctx.self))
+ bank ! Bank.Message.Transfer(x,y,5,ctx.self)
+ Behaviors.same
+ case Account.Balance(x) =>
+ ctx.log.info(s"the balance is $x")
+ Behaviors.same
+ case Account.MovementResponse.Ok =>
+ ctx.log.info(s"ok")
+ bank ! Bank.Message.AccountMessage(x, Account.Message.GetBalance(ctx.self))
+ Behaviors.same
+ case Account.MovementResponse.NotOk =>
+ ctx.log.info(s"not ok")
+ Behaviors.same
+ }
+ }
+ }
+ val bank = ActorSystem(testBehavior, "test-system")
\ No newline at end of file
diff --git a/bank-actors/WireTransfer.scala b/bank-actors/WireTransfer.scala
new file mode 100644
index 0000000..5cb62e0
--- /dev/null
+++ b/bank-actors/WireTransfer.scala
@@ -0,0 +1,37 @@
+import akka.actor.typed.Behavior
+import akka.actor.typed.ActorRef
+import akka.actor.typed.scaladsl.Behaviors
+
+object WireTransfer:
+ def init(
+ from: ActorRef[Account.Message],
+ to: ActorRef[Account.Message],
+ amount: Int,
+ client: ActorRef[Account.MovementResponse]
+ ): Behavior[Account.MovementResponse] = Behaviors.setup { ctx =>
+ def waitForWithdrawal: Behavior[Account.MovementResponse] = Behaviors.receiveMessage {
+ case Account.MovementResponse.Ok =>
+ to ! Account.Message.Deposit(amount, ctx.self)
+ waitForDeposit
+ case Account.MovementResponse.NotOk =>
+ client ! Account.MovementResponse.NotOk
+ Behaviors.stopped
+ }
+ def waitForDeposit: Behavior[Account.MovementResponse] = Behaviors.receiveMessage {
+ case Account.MovementResponse.Ok =>
+ client ! Account.MovementResponse.Ok
+ Behaviors.stopped
+ case Account.MovementResponse.NotOk =>
+ from ! Account.Message.Deposit(amount, ctx.self)
+ client ! Account.MovementResponse.NotOk
+ waitForCancel
+ }
+ def waitForCancel: Behavior[Account.MovementResponse] = Behaviors.receiveMessage {
+ case Account.MovementResponse.Ok =>
+ Behaviors.stopped
+ case Account.MovementResponse.NotOk =>
+ sys.error("wire transfer did not succeed. money stuck in transient state.")
+ }
+ from ! Account.Message.Withdraw(amount, ctx.self)
+ waitForWithdrawal
+ }
diff --git a/bank-actors/build.sbt b/bank-actors/build.sbt
new file mode 100644
index 0000000..4d8b552
--- /dev/null
+++ b/bank-actors/build.sbt
@@ -0,0 +1,11 @@
+name := "lecture-04.5"
+scalaVersion := "3.1.1"
+val AkkaVersion = "2.6.19"
+val Slf4jVersion = "1.7.36"
+libraryDependencies ++= Seq(
+ "com.typesafe.akka" %% "akka-actor-typed" % AkkaVersion,
+ "com.typesafe.akka" %% "akka-actor-testkit-typed" % AkkaVersion,
+ "org.slf4j" % "slf4j-api" % Slf4jVersion,
+ "org.slf4j" % "slf4j-simple" % Slf4jVersion
+)
+Compile / scalaSource := baseDirectory.value
\ No newline at end of file
diff --git a/bank-actors/project/build.properties b/bank-actors/project/build.properties
new file mode 100644
index 0000000..c8fcab5
--- /dev/null
+++ b/bank-actors/project/build.properties
@@ -0,0 +1 @@
+sbt.version=1.6.2
--
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