Last active
May 18, 2022 10:00
-
-
Save nipafx/77dc797e39584b9c8191c71ee7ff3a24 to your computer and use it in GitHub Desktop.
Non-asyncronous EA Async example
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// Two examples [1, 2] from EA Async written without async/await or | |
// (Completable)Futures as straight-forward blocking code. If the | |
// callers want to do something concurrently to `Store::buyItem`, | |
// they just put that call into a new virtual threads. | |
public class Store { | |
private final Bank bank = new Bank(); | |
private final Inventory inventory = new Inventory(); | |
public boolean buyItem_v1(String itemTypeId, int cost) | |
throws InterruptedException { | |
boolean decrementSuccessful = bank.decrement(cost); | |
if (!decrementSuccessful) | |
return false; | |
inventory.give(itemTypeId); | |
return true; | |
} | |
public boolean buyItem_v2(String itemTypeId, int cost) | |
throws InterruptedException, AppException { | |
boolean decrementSuccessful = bank.decrement(cost); | |
if (!decrementSuccessful) | |
return false; | |
try { | |
inventory.give(itemTypeId); | |
return true; | |
} catch (InterruptedException ex) { | |
throw ex; | |
} catch (Exception ex) { | |
bank.refund(cost); | |
throw new AppException(ex); | |
} | |
} | |
} | |
class StoreUser { | |
private final Store store = new Store(); | |
public void useStore(String itemTypeId, int cost) | |
throws InterruptedException { | |
try (var scope = new StructuredTaskScope<Boolean>()) { | |
scope.fork(() -> store.buyItem_v2(itemTypeId, cost)); | |
scope.fork(() -> reorderItem(itemTypeId)); | |
scope.join(); | |
// maybe handle error | |
} | |
} | |
private boolean reorderItem(String itemTypeId) { | |
return true; | |
} | |
} | |
class Bank { | |
public boolean decrement(int cost) | |
throws InterruptedException { | |
return true; | |
} | |
public boolean refund(int cost) | |
throws InterruptedException { | |
return true; | |
} | |
} | |
class Inventory { | |
public String give(String itemTypeId) | |
throws InterruptedException { | |
return ""; | |
} | |
} | |
class AppException extends Exception { | |
public AppException(Throwable cause) { | |
super(cause); | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment