Solutions for Java developers
03/26/09
By Alex Miller
In my previous article I introduced the advantages of the actor
concurrency model over the shared-stated model used by popular
imperative languages like Java. To help you understand actor
concurrency, I explained how it's implemented in Erlang, a
functional language that has been around for a couple of
decades. Erlang's implementation is elegant, but it's a
nonstarter if you're committed to developing applications in a
language that runs on the JVM. So, in this article I'll look at
Erlang-inspired actor implementations in three JVM languages:
Scala, Groovy, and Java.
Libraries that implement actor concurrency on the JVM include
Scala's standard lib; Groovy's GParallelizer; and Java's Kilim,
ActorFoundry, Actors Guild, and Jetlang. I'll use the schoolyard
game Rock-Paper-Scissors as a reference application and
implement it in each library to demonstrate the features and
differences. Each implementation uses two Player actors and a
Coordinator actor. The Coordinator requests each player to play,
and each Player replies with Rock, Paper, or Scissors. The
Coordinator accepts the responses, announces the winner, and
starts over. You can see the message flow illustrated in Figure
1 ...
Read more: Undertstanding actor concurrency, Part 2: Actors on
the JVM http://www.networkworld.com/nljavaworldsente188943
1. Java concurrency with thread gates
http://www.networkworld.com/nljavaworldsente185460
2. MapReduce programming with Apache Hadoop
http://www.javaworld.com/javaworld/jw-09-2008/jw-09-hadoop.html
3. Ted Neward on why Java developers need Scala (JW podcast)
http://www.javaworld.com/podcasts/jtech/2008/061008jtech.html
Most commented: Do you need a college degree to get a
programming job? http://www.javaworld.com/community/node/2651
There's nothing wrong with a software developer getting a
college degree in CompSci, especially when it accompanies an
opportunity to learn useful skills. My problem is with hiring
managers who think the degree is an absolute necessity ...
http://www.javaworld.com/community/node/2651
1. IBM: Better or worse for Java licensing?
http://www.javaworld.com/community/node/2671
2. Java annotations: Use 'em or hate 'em?
http://www.javaworld.com/community/node/2613
3. Developers: The downside of being 'the best'
http://www.javaworld.com/community/node/2652
By all indications IBM is in serious talks to buy Sun
Microsystems this week, an acquisition that would have long-term
impact on Java technology, products, and licensing. Learn more
about the potential impact of this once-in-a-lifetime (and some
say long overdue) deal:
1. IBM and Sun: Future of GlassFish, NetBeans, and JavaFX
http://www.javaworld.com/community/node/2635
2. Google's Dibona says IBM could be good for Java
http://www.networkworld.com/nljavaworldsente188429
3. How IBM + Sun merger would impact IT
http://www.networkworld.com/nljavaworldsente188430
Find more on this topic in JW News & Views
http://www.javaworld.com/news-reviews/
Also see: CEO Payday: What tech chiefs made in 2008 -- Jonathan
Schwartz http://www.networkworld.com/nljavaworldsente188431 You've hit the tip of the iceberg: Read more in JW Blogs
http://www.javaworld.com/community/
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ALSO FEATURED ON JAVAWORLD
Open source Java projects: Jakarta Cactus
http://www.networkworld.com/nljavaworldsente188428
Unit-testing server-side code is famously challenging, but
Jakarta Cactus does make it easier. Learn how Cactus extends
JUnit with an in-container strategy that lets you execute test
cases for servlets, EJBs, and other server-side code. You'll
also learn how to automate your Cactus-based tests.
Writing good unit tests, Part 1: Follow your GUTs
http://www.networkworld.com/nljavaworldsente187286
What do you know about the quality of your unit tests? Probably
not as much as you know about your production code. Klaus Berg
explains why craft matters just as much for test code as for
production code, then provides a comprehensive listing of agile
tools and best practices for improving the quality of your unit
tests.
ActionScript for Java developers, Part 2
http://www.networkworld.com/nljavaworldsente186633
Like other dynamic languages, ActionScript has capabilities and
usage patterns that could take a Java developer by surprise. In
this second half of his guide to the differences between Java
and ActionScript 3, Chet Haase discusses properties, dynamic
behavior, and functions.
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This newsletter is sponsored by Research In Motion
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Research In Motion (RIM) is accepting applications for
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fast, and you'll receive support from RIM every step of the way.
And with 21 million business and personal users (and counting),
BlackBerry App World offers you a world of opportunities.
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UPCOMING ON JAVAWORLD
-Introduction to Lamport's OTP algorithm
-Writing cloud-ready, multicore-friendly code, Part 2
-Jump into JavaFX, Part 4: Advanced APIs
-REST for Java developers, Part 4
-Introduction to Spring MVC
Podcasts:
-Alex Miller: Talkin' about Terracotta
-Make way for Jetty: Coming of age at 12
JavaWorld's Daily Brew - Starting conversations in the Java
developer community
http://www.javaworld.com/community
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