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Akka Java Documentation Release 2.2.5
Akka Java Documentation Release 2.2.5 Typesafe Inc February 19, 2015 CONTENTS 1 Introduction 1 1.1 What is Akka?............................................1 1.2 Why Akka?..............................................3 1.3 Getting Started............................................3 1.4 The Obligatory Hello World.....................................7 1.5 Use-case and Deployment Scenarios.................................8 1.6 Examples of use-cases for Akka...................................9 2 General 10 2.1 Terminology, Concepts........................................ 10 2.2 Actor Systems............................................ 12 2.3 What is an Actor?.......................................... 14 2.4 Supervision and Monitoring..................................... 16 2.5 Actor References, Paths and Addresses............................... 19 2.6 Location Transparency........................................ 25 2.7 Akka and the Java Memory Model.................................. 26 2.8 Message Delivery Guarantees.................................... 28 2.9 Configuration............................................. 33 3 Actors 65 3.1 Actors................................................ 65 3.2 Typed Actors............................................. 84 3.3 Fault Tolerance............................................ 88 3.4 Dispatchers.............................................. 103 3.5 Mailboxes.............................................. 106 3.6 Routing................................................ 111 3.7 Building Finite State Machine -
Up up and Out: Scaling Software with Akka
UP UP AND OUT: SCALING SOFTWARE WITH AKKA Jonas Bonér CTO Typesafe @jboner Scaling software with Jonas Bonér CTO Typesafe @jboner ScalingScaling softwaresoftware with with ScalingScaling softwaresoftware with with Akka (Áhkká) The name comes from the goddess in the Sami (native swedes) mythology that represented all the wisdom and beauty in the world. It is also the name of a beautiful mountain in Laponia in the north part of Sweden ScalingScaling softwaresoftware with with Manage System Overload Scale UP & Scale OUT How can we achieve this? How can we achieve this? Let’s use Actors How can we achieve this? What is an Actor? What is an Actor? What is an Actor? • Akka's unit of code organization is called an Actor What is an Actor? • Akka's unit of code organization is called an Actor • Like Java EE servlets and session beans, Actors is a model for organizing your code that keeps many “policy decisions” separate from the business logic What is an Actor? • Akka's unit of code organization is called an Actor • Like Java EE servlets and session beans, Actors is a model for organizing your code that keeps many “policy decisions” separate from the business logic • Actors may be new to many in the Java community, but they are a tried-and-true concept (Hewitt 1973) used for many years in telecom systems with 9 nines uptime Program at a Higher Level Program at a Higher Level Program at a Higher Level • Never think in terms of shared state, state visibility, threads, locks, concurrent collections, thread notifications etc. -
A Software Framework for the Actor Model Focusing on the Optimization of Message Passing
AICT 2018 : The Fourteenth Advanced International Conference on Telecommunications Actor4j: A Software Framework for the Actor Model Focusing on the Optimization of Message Passing David Alessandro Bauer, Juho Mäkiö Department of Informatics and Electronics University of Applied Sciences Emden/Leer Emden, Germany Email: [email protected], [email protected] Abstract—Common actor implementations often use also the Scale Cube by Abbott [6], which describes the three standardized thread pools without special optimization for the dimensions of scalability. message passing. For that, a high-performance solution was To ensure high parallelization, its one benefit to use worked out. The actor-oriented software framework Akka uses multi-core systems. The computer world of the last few internally a ForkJoinPool that is intended for a MapReduce years has been characterized by a change ("The Free Lunch approach. However, the MapReduce approach is not relevant for message passing, as it may lead to significant performance Is Over" [7]) from constantly increasing computing power losses. One solution is to develop a thread pool that focuses on to multi-core systems due to technical limitations. In the message passing. In the implementation of the Actor4j particular, technical progress always lags behind practical framework, the message queue of the actors is placed in requirements (Wirth's law [8]). Up to now, Moore's law was threads to enable an efficient message exchange. The actors are “that the number of transistors available to semiconductor operated directly from this queue (injecting the message), manufacturers would double approximately every 18 to 24 without further ado. -
Reactive Programming with Scala, Lagom, Spark, Akka and Play
Issue October 2016 | presented by www.jaxenter.com #53 The digital magazine for enterprise developers Reactive Programming with Scala, Lagom, Spark, Akka and Play Interview with Scala creator Martin Odersky The state of Scala The Lagom Framework Lagom gives the developer a clear path DevOpsCon 2016: Our mission statement This is how we interpret modern DevOps ©istockphoto.com/moorsky Editorial Reactive programming is gaining momentum “We believe that a coherent approach to systems architec- If the definition “stream of events” does not satisfy your ture is needed, and we believe that all necessary aspects are thirst for knowledge, get ready to find out what reactive pro- already recognized individually: we want systems that are Re- gramming means to our experts in Scala, Lagom, Spark, Akka sponsive, Resilient, Elastic and Message Driven. We call these and Play. Plus, we talked to Scala creator Martin Odersky Reactive Systems.” – The Reactive Manifesto about the impending Scala 2.12, the current state of this pro- Why should anyone adopt reactive programming? Because gramming language and the technical innovations that await it allows you to make code more concise and focus on im- us. portant aspects such as the interdependence of events which Thirsty for more? Open the magazine and see what we have describe the business logic. Reactive programming means dif- prepared for you. ferent things to different people and we are not trying to rein- vent the wheel or define this concept. Instead we are allowing Gabriela Motroc, Editor our authors to prove how Scala, Lagom, Spark, Akka and Play co-exist and work together to create a reactive universe. -
Lightweight Affinity and Object Capabilities in Scala
http://www.diva-portal.org Postprint This is the accepted version of a paper presented at ACM SIGPLAN International Conference on Object-Oriented Programming, Systems, Languages, and Applications (OOPSLA). Citation for the original published paper: Haller, P., Loiko, A. (2016) LaCasa: Lightweight Affinity and Object Capabilities in Scala. In: Proceedings of the 2016 ACM SIGPLAN International Conference on Object-Oriented Programming, Systems, Languages, and Applications (pp. 272-291). Association for Computing Machinery (ACM) https://doi.org/10.1145/3022671.2984042 N.B. When citing this work, cite the original published paper. © Author | ACM 2016. This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in Proceedings of the 2016 ACM SIGPLAN International Conference on Object-Oriented Programming, Systems, Languages, and Applications, http://dx.doi.org/10.1145/3022671.2984042. Permanent link to this version: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-197902 LACASA: Lightweight Affinity and Object Capabilities in Scala Philipp Haller Alex Loiko KTH Royal Institute of Technology, Sweden Google, Sweden ∗ [email protected] [email protected] Abstract difficulty of reasoning about program behavior and software Aliasing is a known source of challenges in the context of architecture [3], and it can introduce data races in concur- imperative object-oriented languages, which have led to im- rent programs. These observations have informed the devel- portant advances in type systems for aliasing control. How- opment of a number of type disciplines aimed at providing ever, their large-scale adoption has turned out to be a surpris- static aliasing properties, such as linear types [33, 51, 64], ingly difficult challenge. -
A Web-Based System for Executing Interactive Scala Programming Exercises in Browser
Aalto University School of Science Master's Programme in Information Networks Anastasia Lipi¨ainen A Web-Based System for Executing Interactive Scala Programming Exercises in Browser Master's Thesis Espoo, November 27, 2016 Supervisor: Professor Lauri Malmi Advisors: Otto Sepp¨al¨aD.Sc. (Tech) Juha Sorva D.Sc. (Tech) Aalto University School of Science ABSTRACT OF Master's Programme in Information Networks MASTER'S THESIS Author: Anastasia Lipi¨ainen Title: A Web-Based System for Executing Interactive Scala Program- ming Exercises in Browser Date: November 27, 2016 Pages: vii + 120 Major: Information Networks Code: SCI3047 Supervisor: Professor Lauri Malmi Advisors: Otto Sepp¨al¨aD.Sc. (Tech), Juha Sorva D.Sc. (Tech) When first introduced to programming, students are often assigned to write mere code snippets that only produce a numerical output with the help of a simple control structure. The students are left unimpressed as they fail to see the real utility that learning to program holds. By assigning students real-world programming problems, such as games and media computation exercises, we showcase real applications for programming. At the beginning of their first programming course, students are already used to working with modern, interactive, and visually impressive interfaces. However, they cannot be expected to produce the graphical user interfaces required to take the full advantage of media content. Previously, we have distributed interfaces implemented with Swing as program code for local execution; the practise does not allow the easy updating of assignment related code and achieving a usable interface is tiresome with the use of Swing. To address the issues of the current process, we developed a web-based system that allows the execution of interactive Scala programs in a browser. -
The Lift Approach
Science of Computer Programming 102 (2015) 1–19 Contents lists available at ScienceDirect Science of Computer Programming www.elsevier.com/locate/scico Analyzing best practices on Web development frameworks: The lift approach ∗ María del Pilar Salas-Zárate a, Giner Alor-Hernández b, , Rafael Valencia-García a, Lisbeth Rodríguez-Mazahua b, Alejandro Rodríguez-González c,e, José Luis López Cuadrado d a Departamento de Informática y Sistemas, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain b Division of Research and Postgraduate Studies, Instituto Tecnológico de Orizaba, Mexico c Bioinformatics at Centre for Plant Biotechnology and Genomics, Polytechnic University of Madrid, Spain d Computer Science Department, Universidad Carlos III de Madrid, Spain e Department of Engineering, School of Engineering, Universidad Internacional de La Rioja, Spain a r t i c l e i n f oa b s t r a c t Article history: Choosing the Web framework that best fits the requirements is not an easy task for Received 1 October 2013 developers. Several frameworks now exist to develop Web applications, such as Struts, Received in revised form 18 December 2014 JSF, Ruby on Rails, Grails, CakePHP, Django, and Catalyst. However, Lift is a relatively new Accepted 19 December 2014 framework that emerged in 2007 for the Scala programming language and which promises Available online 5 January 2015 a great number of advantages and additional features. Companies such as Siemens© and Keywords: IBM®, as well as social networks such as Twitter® and Foursquare®, have now begun to Best practices develop their applications by using Scala and Lift. Best practices are activities, technical Lift or important issues identified by users in a specific context, and which have rendered Scala excellent service and are expected to achieve similar results in similar situations. -
Comparing Languages for Engineering Server Software: Erlang, Go, and Scala with Akka
Comparing Languages for Engineering Server Software: Erlang, Go, and Scala with Akka Ivan Valkov, Natalia Chechina, and Phil Trinder School of Computing Science, University of Glasgow G12 8RZ, United Kingdom [email protected], {Natalia.Chechina, Phil.Trinder}@glasgow.ac.uk Abstract functional or object-oriented, with high-level coordination models, Servers are a key element of current IT infrastructures, and must e.g. actors as in Erlang [2] or a process algebra as in Go [6]. Indeed, often deal with large numbers of concurrent requests. The program- the success of some server-based companies is even attributed to ming language used to construct the server has an important role their use of specific languages. As examples WhatsApp’s success in engineering efficient server software, and must support massive is attributed to their use of Erlang [27]; the video streaming leader concurrency on multicore machines with low communication and Twitch uses Go to serve millions of users a day [13]. Research synchronisation overheads. contributions of this paper include the following: This paper investigates 12 highly concurrent programming lan- • A survey of programming language characteristics relevant for guages suitable for engineering servers, and analyses three repre- servers (Section 2.1). sentative languages in detail: Erlang, Go, and Scala with Akka. • The design and implementation of three benchmarks to analyse We have designed three server benchmarks that analyse key per- the multicore server capabilities of Erlang, Go, and Scala with formance characteristics of the languages. The benchmark results Akka (Section 3). suggest that where minimising message latency is crucial, Go and Erlang are best; that Scala with Akka is capable of supporting the • An evaluation of Erlang, Go, and Scala with Akka for key largest number of dormant processes; that for servers that frequently server capabilities, i.e. -
N2O Most Powerful Erlang Web Framework @5HT How Do I Shot Web? Micro REST
N2O Most Powerful Erlang Web Framework @5HT How do I shot Web? Micro REST Python Flask Ruby Sinatra PHP Silex Scala Scalatra Concurrency in Mind Ruby Celluloid PHP React PHP phpDaemon Java+Scala Play SPA Angular Meteor Ember Chaplin Brunch D3 Knockout React Backbone jQuery Functional DSL Scala Lift Erlang Nitrogen Haskell BlazeHtml OCaml Ocsigen F# WebSharper Clojure Laser Enlive Compojure Ring Hiccup ClojureScript Om http-kit aleph noir JVM Elixir Weber def action(_, conn) do {:render, [project: "simpleTodo"], []} end def add([body: body], _conn) do {:json, [response: "ok"], [{"Content-Type", "application/json"}]} end def wrong(_, _) do {:redirect, "/"} end Erlang ChicagoBoss DTL Engine Database Connectivity PubSub Ruby on Rails like Nitrogen N2O ~2000 LOC One Process per Connection Binary Page Construction Zero Bridge GProc Pub/Sub WebSockets, KVS DB Tuned Layers static and dynamic Routing Path cleaned Query Parser Session Cookies stored in ETS cached DTL Templates optimized Nitrogen DSL rendering HTML Elements binaries JavaScript Actions deferred Layers Performance components TCP conn (K) PHP5 FCGI Simple Script <?php ?> 5 Nitrogen No session, No DSL, DTL 1 N2O Sessions, DSL, DTL 7 N2O Sessions, no DSL, DTL 10 N2O No Sessions, no DSL, DTL 13 On same machine raw webserver performance measured with wrk: NGINX -- 60K Cowboy -- 30K Measuring Tools requests pages/sec latency (ms) wrk 15K 13628.86 18.88 ab 10K 5464.63 190 httperf 10K 3623.50 200 siege 1K 884.51 430 On same machine raw webserver performance measured with wrk: NGINX -- 60K Cowboy -- 30K Decreasing Latency From 2x to ∞ Deliver HTML ASAP Deferred JavaScript delivery after WebSocket connection established <script> TransitionProcess = '<0.7780.5>' </script> socket.send(["N2O",TransitionProcess]). -
Full-Graph-Limited-Mvn-Deps.Pdf
org.jboss.cl.jboss-cl-2.0.9.GA org.jboss.cl.jboss-cl-parent-2.2.1.GA org.jboss.cl.jboss-classloader-N/A org.jboss.cl.jboss-classloading-vfs-N/A org.jboss.cl.jboss-classloading-N/A org.primefaces.extensions.master-pom-1.0.0 org.sonatype.mercury.mercury-mp3-1.0-alpha-1 org.primefaces.themes.overcast-${primefaces.theme.version} org.primefaces.themes.dark-hive-${primefaces.theme.version}org.primefaces.themes.humanity-${primefaces.theme.version}org.primefaces.themes.le-frog-${primefaces.theme.version} org.primefaces.themes.south-street-${primefaces.theme.version}org.primefaces.themes.sunny-${primefaces.theme.version}org.primefaces.themes.hot-sneaks-${primefaces.theme.version}org.primefaces.themes.cupertino-${primefaces.theme.version} org.primefaces.themes.trontastic-${primefaces.theme.version}org.primefaces.themes.excite-bike-${primefaces.theme.version} org.apache.maven.mercury.mercury-external-N/A org.primefaces.themes.redmond-${primefaces.theme.version}org.primefaces.themes.afterwork-${primefaces.theme.version}org.primefaces.themes.glass-x-${primefaces.theme.version}org.primefaces.themes.home-${primefaces.theme.version} org.primefaces.themes.black-tie-${primefaces.theme.version}org.primefaces.themes.eggplant-${primefaces.theme.version} org.apache.maven.mercury.mercury-repo-remote-m2-N/Aorg.apache.maven.mercury.mercury-md-sat-N/A org.primefaces.themes.ui-lightness-${primefaces.theme.version}org.primefaces.themes.midnight-${primefaces.theme.version}org.primefaces.themes.mint-choc-${primefaces.theme.version}org.primefaces.themes.afternoon-${primefaces.theme.version}org.primefaces.themes.dot-luv-${primefaces.theme.version}org.primefaces.themes.smoothness-${primefaces.theme.version}org.primefaces.themes.swanky-purse-${primefaces.theme.version} -
A Sampling of NYC Python My Startups And
A Startup Junkie's Journey to Python via Java, Ruby and Scala Andy Parsons @andyparsons Happiness Speed Magic Readability My Startups and Their Stacks What Are We Building? And in general... Happify is an angel-funded consumer Github Project Relative % destination “life game.” BUSINESS WEB API SERVICES DATABASES TEAM SIZE HTML5, Mobile, and Facebook front ends. Pro Photo ASP.NET C#, Perl SQL Server 12 Currently in stealth mode. Scala Ruby 4% 60% Hyperlocal PostgreSQL, How do they “Stack” Up? RoR Sinatra Scala 10 Content MongoDB (Geolocation ) Score is based on: Ereading and Python Book RoR Scalatra Scala/Java MongoDB 8 Green = 2 Recommende Yellow = 1 23 36% r Red = 0 Python/ PostgreSQL, Life Gaming Flask Python 3 Gevent MongoDB 18 Building Happify: Comparing Language Options BASICS 8 PACKAGING / FRAMEWORKS SPEED CONCURRENCY TOOLING DEPLOYMENT TESTING DEPENDENCIES / LIBS Growing collection Healthy, lots of Fast enough Achieved through Process.fork Gems Capistrano Mature of libs, but weak in RUBY choice NLP Early for native Scala Ruby Python Still early. IDE’s Complex. JARs, SBT, Ivy, Fast! Real concurrency, Akka ? Maturing scala libraries, rely SCALA weak. Maven. on Java interop A Sampling of NYC Python Achieved through Healthy, lots of Massive collection Fast enough Eggs Fabric Mature Gratuitous Perf Charts! PYTHON multiprocessing choice of libraries FLAME BAIT HAPPINESS / COMMUNITY / PROPENSITY FOR MATURITY / READABILITY HIRING PRODUCTIVITY ACTIVITY MAGIC STABILITY OK. Emphasis Metaprogramming is sometimes Stable, but much Tough. Medium RUBY metaprogramming can High Huge and active abused. RoR is too magical and catchup remaining for learning curve, present challenges. many imitated its philosophy gems to support 1.9 hard to find seasoned devs Too many ways to accomplish Language spec Very difficult. -
Akka, Play & Scala in Practice – Stjepan
1 Akka, Play & Scala u praksi STJEPAN BULJAT ETNA D.O.O. [email protected] @sbuljat JavaCro ‘13 – 2nd International Java Conference in Croatia 2 O predavaču… Radim kao voditelj tima za razvoj i istraživanje u tvrtki Etna d.o.o. Završio FER (mag.ing.comp.) i EFZG (univ.spec.oec ) Povijest programiranja: Pascal C Smalltalk Java Scala je privatna tvrtka iz Zagreba osnovana 1990. godine Zapošljava 30ak djelatnika 22 godine iskustva u bankarstvu i informatici Usluge razvoja i uvođenja informatičkih rješenja uz primjenu suvremenih informacijskih tehnologija Usluge prilagodbe i integracije postojećih informatičkih rješenja Usluge poslovne analize i poslovnih konzultacija All rights reserved. Copyright © 2013 Etna d.o.o. | www.etna.hr 16.6.2013. 21:33 3 Akka - Uvod Threads are bad? Ne nužno, ali apstrakcija može biti korisna… tu dolazi Akka Akka je middleware koji omogućuje izgradnju visoko konkurentnih i distribuiranih event-driven aplikacija koje su otporne na greške (eng. fault tolerant ) Komunikacijski model se bazira na asinkronoj razmjeni poruka između dijelova sustava Omogućuje konkurentnost bez dijeljenog promjenjivog stanja i zaključavanja resursa Osnovni gradivni element u Akka-i je ACTOR Location Transparent & Distributable by Design Actor Model je definirao Carl Hewitt 1973, ali zasluge za popularizaciju ipak pripadaju Erlangu Actori omogućuju Jednostavnu apstrakciju konkurentnosti i paralelizma Asinkroni, ne blokirajući i jako učinkovit event-driven programski model Lightweight event-driven procese (cca 2.7M actora po GB Heap-a) All rights reserved. Copyright © 2013 Etna d.o.o. | www.etna.hr 16.6.2013. 21:33 4 Akka – Actor Actor može biti alternativa za: Thread, Component, Listener , Service, Load balancer , EJB SB / MDB, … Osnovne actor operacije DEFINE CREATE SEND BECOME SUPERVISE All rights reserved.