Добро пожаловать, дорогой читатель, на мою статью. В этой статье мы обсудим фреймворк, изначально созданный для языка Scala, но также и с версией для Java, которая предлагает новый способ разработки параллельных приложений: Akka.
Традиционная модель параллелизма: потоки
Традиционно, когда мы работаем с параллелизмом, мы используем потоки, которым иногда нужно делиться ресурсами друг с другом. Чтобы обеспечить изоляцию выполнения, мы начинаем вводить блоки выполнения с синхронизированной политикой. По мере роста системы добавляется все больше блоков такого типа, что иногда приводит нас в состояние взаимоблокировок, когда процессы находятся в состоянии постоянной блокировки, поскольку процесс пытается получить доступ к ресурсу, который уже заблокирован предшественником. процесс его выполнения потоком. Мы можем увидеть пример этой ситуации на рисунке ниже, где три потока «конкурируют» за использование ресурсов и входят в состояние тупика:
Размышляя об этом, он был разработан в 1973 году Карлом Хьюиттом, Питером Бишопом и Ричардом Штайгером, одна статья под названием «Универсальный формализм акторов для искусственного интеллекта». В этой статье представлена концепция актеров, о которой мы поговорим далее.
Модель параллелизма актерами
В модели параллелизма актеров у нас появилась новая концепция развития. В этой модели вся обработка должна быть разбита на логические единицы, называемые действующими лицами, каждая из которых имеет свою роль и свой правильный порядок в потоке. Простой способ понять эту модель — представить процесс реальной жизни, где «актерами» являются люди. Представьте себе поток, в котором человек A получает сообщение для отправки по почте человеку B, в этом случае у нас будет следующий поток действий в упрощенной форме:
- Человек А получает письмо;
- Лицо А доставляет письмо администратору почты;
- Администратор организует письма и доставляет их почтальону;
- Почтальон направляется в резиденцию человека Б и дает письмо;
- Человек Б читает письмо;
В этом простом примере мы видим, что каждый человек является актером в потоке. Важный момент, который следует отметить в этом примере, заключается в том, что все действия являются асинхронными среди действующих лиц: когда человек А вручает письмо регистратору, ему не нужно ждать доставки письма, чтобы прекратить его участие в потоке.
Именно из этих концепций Akka строит свою обработку: акторы работают независимо от шагов потока, а их взаимодействия происходят друг с другом асинхронно.
Диаграмма ниже иллюстрирует эту модель:
PS: В приведенной выше модели мы видим, что актеры находятся в некой иерархии, где из корневого актера вызываются другие акторы. Эта иерархия является «местом» создания действующих лиц в потоке, где корневой субъект создается в основном системном потоке. В ходе практической работы мы можем более четко увидеть, как работает эта иерархия.
Руки вверх
Для этого мы будем использовать Eclipse Luna и Maven 3.0. Сначала создайте простой проект Maven без определенного архетипа и поместите наши зависимости в файл pom.xml:
<project xmlns=”http://maven.apache.org/POM/4.0.0″ xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=”http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd”> <modelVersion>4.0.0</modelVersion> <groupId>br.com.alexandreesl.handson</groupId> <artifactId>HandsOnAkka</artifactId> <version>0.0.1-SNAPSHOT</version> <dependencies> <dependency> <groupId>com.typesafe.akka</groupId> <artifactId>akka-actor_2.10</artifactId> <version>2.2.3</version> </dependency> </dependencies> </project>
Как мы видим выше, просто включите в проект зависимость «akka-actor_2.10». В Akka у нас есть концепция серверов акторов, где мы запускаем наши процессы в модели Akka. Вы можете создавать экземпляры этих серверов и вызывать их удаленно, но в этом примере мы запустим один из них автономно, чтобы сохранить простоту в обучении.
Для начала давайте создадим основной класс проекта, где мы запустим сервер актеров. Код ниже выполняет эту задачу:
package br.com.alexandreesl.handson;
import akka.actor.ActorSystem;
public class ActorServer {
public static void main(String[] args) {
ActorSystem server = ActorSystem.create(“ActorServer”);
}
}
Как мы видим, довольно просто создать сервер актеров с одной строкой. Важным моментом при создании сервера является то, что он создает новый поток, который позволяет программе работать неопределенно долго.
В этом примере мы смоделируем отправку письма от человека A человеку B, как мы говорили на протяжении всей статьи. Для этого мы сделаем звонок первому актеру потока, то есть человеку, который получит письмо и доставит его на почту, чтобы отправить:
package br.com.alexandreesl.handson;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.Props;
public class ActorServer {
public static void main(String[] args) {
ActorSystem server = ActorSystem.create(“ActorServer”);
ActorRef personA = server.actorOf(Props.create(PersonA.class),
“PersonA”);
personA.tell(“Message to be delivered “, ActorRef.noSender());
}
}
В приведенном выше коде мы создаем ссылку (ActorRef) для субъекта personA и передаем письмо тому же. Чтобы создать актера, просто создайте класс, который расширяет класс UntypedActor, как мы увидим ниже.
package br.com.alexandreesl.handson;
import akka.actor.ActorRef;
import akka.actor.Props;
import akka.actor.UntypedActor;
import akka.event.Logging;
import akka.event.LoggingAdapter;
public class PersonA extends UntypedActor {
private ActorRef postRecepcionist;
private LoggingAdapter log = Logging.getLogger(getContext().system(), this);
@Override
public void preStart() throws Exception {
super.preStart();
postRecepcionist = getContext().actorOf(
Props.create(PostReceptionist.class), “PostRecepcionist”);
}
@Override
public void onReceive(Object message) throws Exception {
log.info(“Receiving the letter”);
log.info(“Going to the post office”);
log.info(“Delivering the letter to the post recepcionist”);
postRecepcionist.tell(message, getSelf());
}
}
В приведенном выше коде мы создаем ссылку на регистратора почтового отделения в событии preStart и реализуем сообщение, передаваемое регистратору, в основном методе актера «OnReceive». В жизненном цикле актеров в Akka есть 4 события, в которые мы можем вставить дополнительный код: preStart, preRestart, postRestart и postStop. По сути, у актеров есть несколько «воплощений» (экземпляров), которые происходят каждый раз, когда основной метод актера «OnReceive» генерирует исключение, когда согласно набору политик супервизора, актер может быть перевоплощен (перезапущен) и завершен ( стоп). Позже мы поговорим более подробно о политике, но сейчас мы можем видеть на диаграмме ниже жизненный цикл действующих лиц:
Последнее, что нужно сказать о приведенном выше коде, — это использование API протоколирования Akka, в котором мы можем регистрировать некоторые сообщения, представляющие обработку, которую должен выполнять актер. Когда мы используем API Akka, помимо традиционного информационного журнала, который можно найти в Java, также записывается иерархия актера в потоке, облегчая дальнейший анализ. Остальные коды примера аналогичны Actor PersonA и представляют только прохождение иерархии потока сообщений, поэтому ниже мы перечислим остальную часть этого первого примера кода:
package br.com.alexandreesl.handson;
import akka.actor.ActorRef;
import akka.actor.Props;
import akka.actor.UntypedActor;
import akka.event.Logging;
import akka.event.LoggingAdapter;
public class PostReceptionist extends UntypedActor {
private ActorRef postMan;
private LoggingAdapter log = Logging.getLogger(getContext().system(), this);
@Override
public void preStart() throws Exception {
super.preStart();
postMan = getContext().actorOf(Props.create(PostMan.class), “PostMan”);
}
@Override
public void onReceive(Object message) throws Exception {
log.info(“Organizing the letters”);
log.info(“Delivering the letters to the Postman”);
postMan.tell(message, getSelf());
}
}
package br.com.alexandreesl.handson;
import akka.actor.ActorRef;
import akka.actor.Props;
import akka.actor.UntypedActor;
import akka.event.Logging;
import akka.event.LoggingAdapter;
public class PostMan extends UntypedActor {
private ActorRef personB;
private LoggingAdapter log = Logging.getLogger(getContext().system(), this);
@Override
public void preStart() throws Exception {
super.preStart();
personB = getContext().actorOf(Props.create(PersonB.class), “PersonB”);
}
@Override
public void onReceive(Object message) throws Exception {
log.info(“Go to the address with the letter”);
log.info(“Deliver the letter to personB”);
personB.tell(message, getSelf());
}
}
package br.com.alexandreesl.handson;
import akka.actor.UntypedActor;
import akka.event.Logging;
import akka.event.LoggingAdapter;
public class PersonB extends UntypedActor {
private LoggingAdapter log = Logging.getLogger(getContext().system(), this);
@Override
public void onReceive(Object message) throws Exception {
log.info(“Reads the letter”);
}
}
Наконец, для запуска примера мы просто выбираем класс ActorServer и запускаем его так же, как программу Java (запускаем как> Java-приложение). Журнал показывает выполнение программы:
[INFO] [12/25/2014 14:12:48.439] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:12:48.439] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:12:48.439] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:12:48.439] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:12:48.439] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:12:48.442] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:12:48.442] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:12:48.442] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter
As we can see above, all messages were processed in the order of the implemented flow. An important point to note is that the processing of messages by the actors is asynchronous, that is, if we put more messages, the actors will not wait for the end of the processing to process the next message. To illustrate, let’s modify the main class and include a message loop:
for (int i = 0; i < 10; i++) personA.tell(“Message to be delivered ” + i, ActorRef.noSender());
With the above modification, if we execute the program again, we will have the following log:
[INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.584] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:16:33.585] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:16:33.587] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.587] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.587] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.587] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:16:33.588] [ActorServer-akka.actor.default-dispatcher-4] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter
As seen above, executions of the actors interspersed with each other, demonstrating the asynchrony of executions.
Transactions & fault tolerance
The reader may be wondering how the Akka address issues such as transactional code and fault tolerance in cases of executions in which exceptions occur during execution.
For transactional, Akka provides another component called “akka-Transactor”, which uses classes like the Coordinator, where we create code defined as “atomic”, ie, that must be performed in its entirety, or have your changes aborted in failure cases.
To the question of fault tolerance, the Akka provides the concept of supervisors, where an actor can also be a supervisor. When an actor is also a supervisor, it implements a policy that will affect all actors under the supervisor. In our example of hands-on, if we put for example the receptionist as a supervisor, the policy will be applied to both the postman and the personB, which are the next actors in the running. We have in the framework various supervisory models, where actors can either be “reincarnated” or finalized. In addition, you can also define whether the policy will be performed (restart / stop) for all supervised actors, or just for the actor that failed.
To illustrate the use, let’s add the following code snippet in the receptionist actor:
.
.
.
@Override
public SupervisorStrategy supervisorStrategy() {
return new OneForOneStrategy(-1, Duration.Inf(),
new Function<Throwable, Directive>() {
public Directive apply(Throwable t) throws Exception {
return OneForOneStrategy.restart();
}
});
}
In the passage above, we define a policy for all actors below the receptionist, where in case of failure, the actor that failed will be restart.
To simulate a fault, we modify the code in personB actor as follow:
package br.com.alexandreesl.handson;
import scala.Option;
import akka.actor.UntypedActor;
import akka.event.Logging;
import akka.event.LoggingAdapter;
public class PersonB extends UntypedActor {
int counter = 0;
private LoggingAdapter log = Logging.getLogger(getContext().system(), this);
@Override
public void preRestart(Throwable reason, Option<Object> message)
throws Exception {
log.info(“THE PERSONB IS BOOTING!”);
super.preRestart(reason, message);
}
@Override
public void onReceive(Object message) throws Exception {
log.info(“Reads the letter”);
if (counter % 2 != 0)
throw new RuntimeException(“ERROR!”);
counter++;
}
}
When we run the example again, we have the following execution log, showing the implementation of the policy:
[INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Receiving the letter [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Going to the post office [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-3] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA] Delivering the letter to the post recepcionist [INFO] [12/25/2014 14:23:54.807] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.808] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.808] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.808] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.808] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.816] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.816] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.816] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.816] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Organizing the letters [INFO] [12/25/2014 14:23:54.816] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist] Delivering the letters to the Postman [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.817] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.818] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.818] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [INFO] [12/25/2014 14:23:54.818] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Go to the address with the letter [INFO] [12/25/2014 14:23:54.818] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan] Deliver the letter to personB [ERROR] [12/25/2014 14:23:54.823] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] ERROR! java.lang.RuntimeException: ERROR! at br.com.alexandreesl.handson.PersonB.onReceive(PersonB.java:29) at akka.actor.UntypedActor$$anonfun$receive$1.applyOrElse(UntypedActor.scala:167) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498) at akka.actor.ActorCell.invoke(ActorCell.scala:456) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237) at akka.dispatch.Mailbox.run(Mailbox.scala:219) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [INFO] [12/25/2014 14:23:54.823] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] THE PERSONB IS BOOTING! [INFO] [12/25/2014 14:23:54.868] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:23:54.868] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [ERROR] [12/25/2014 14:23:54.868] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] ERROR! java.lang.RuntimeException: ERROR! at br.com.alexandreesl.handson.PersonB.onReceive(PersonB.java:29) at akka.actor.UntypedActor$$anonfun$receive$1.applyOrElse(UntypedActor.scala:167) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498) at akka.actor.ActorCell.invoke(ActorCell.scala:456) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237) at akka.dispatch.Mailbox.run(Mailbox.scala:219) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [INFO] [12/25/2014 14:23:54.868] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] THE PERSONB IS BOOTING! [INFO] [12/25/2014 14:23:54.868] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:23:54.868] [ActorServer-akka.actor.default-dispatcher-2] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [ERROR] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] ERROR! java.lang.RuntimeException: ERROR! at br.com.alexandreesl.handson.PersonB.onReceive(PersonB.java:29) at akka.actor.UntypedActor$$anonfun$receive$1.applyOrElse(UntypedActor.scala:167) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498) at akka.actor.ActorCell.invoke(ActorCell.scala:456) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237) at akka.dispatch.Mailbox.run(Mailbox.scala:219) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [INFO] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] THE PERSONB IS BOOTING! [INFO] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [ERROR] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] ERROR! java.lang.RuntimeException: ERROR! at br.com.alexandreesl.handson.PersonB.onReceive(PersonB.java:29) at akka.actor.UntypedActor$$anonfun$receive$1.applyOrElse(UntypedActor.scala:167) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498) at akka.actor.ActorCell.invoke(ActorCell.scala:456) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237) at akka.dispatch.Mailbox.run(Mailbox.scala:219) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [INFO] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] THE PERSONB IS BOOTING! [INFO] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [INFO] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] Reads the letter [ERROR] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] ERROR! java.lang.RuntimeException: ERROR! at br.com.alexandreesl.handson.PersonB.onReceive(PersonB.java:29) at akka.actor.UntypedActor$$anonfun$receive$1.applyOrElse(UntypedActor.scala:167) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498) at akka.actor.ActorCell.invoke(ActorCell.scala:456) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237) at akka.dispatch.Mailbox.run(Mailbox.scala:219) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386) at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [INFO] [12/25/2014 14:23:54.869] [ActorServer-akka.actor.default-dispatcher-5] [akka://ActorServer/user/PersonA/PostRecepcionist/PostMan/PersonB] THE PERSONB IS BOOTING!
I encourage the reader to go deeper in these and other subjects of the framework
Conclusion
And so we conclude our article on the Akka framework. With a very interesting concept and a extensible parallel processing model, the framework is a good option that should be evaluated by all developers and architects who want to explore other ways beyond the traditional thread pool. Many thanks to all who have accompanied me in this article, until next time.
Links