title: JRuby: Ready for Action
gradient: dark blue black

h1. JRuby: Ready for Action

Charles Oliver Nutter and Thomas Enebo @ Prague, EuRuKo 2008

The JRuby Guys, Sun Microsystems

Adapted S6/S9[1] Version from "Original Slide Deck":http://dist.codehaus.org/jruby/talks/EuRuKo%202008.odp

<hr>
fn1. ("Source":http://slideshow.rubyforge.org/svn/samples/jruby.textile)

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h1. Agenda

* JRuby overview
* JRuby enhancements and additions
* Swing programming
* Demo: Swing in Ruby
* Web applications
* Demo: JRuby on Rails
* Graphics and applets (that don't suck)
* Demo: Pretty graphics!

h1. The JRuby Guys

* Charles Oliver Nutter and Thomas Enebo
* Longtime Java developers (10+ yrs each)
* Engineers at Sun Microsystems for 1 yr
* Full-time JRuby developers
* Also working on JVM dynlang support
* Wide range of past experience
** C, C++, C#, Perl, Python, Delphi, Lisp, Scheme
** Java EE and ME, JINI, WS

h1. JRuby

* Java implementation of Ruby language
** "It's just Ruby!"
* Started in 2002, open source, many contributors
** Ola Bini, Marcin Mielzinsky, Nick Sieger, Bill Dortch, Vladimir Sizikov, MenTaLguY
* Aiming for compatibility with current Ruby version
** Ruby 1.8.6 patchlevel 111 (114 was just released)
* Improvements on Ruby
** Native threading, better performance, many libraries

h1. JRuby 1.1 Released!

* Announced today: JRuby 1.1 is finished!
* Massive improvements over 1.0
** Full compiler for Ruby code to JVM bytecode
** Performance is many times better across the board
** New Regexp impl with full Oniguruma features
** New rewritten IO subsystem to parallel Ruby behavior
** Reduced memory footprint
** Best compatibility level ever
* Ready for production use (and already being used)
* Quick series of maintenance releases coming

h1. Compatibility

* Applications are king
** Rails, Rubygems, Rake, Rspec, ...
* Testing rulez (~42,000 expectations/assertions)
** Prevents regressions
** Helps to better define Ruby
* Prevents fragmenting a community
** Like Sapphire or ...Sapphire???

h1. Java == A Dirty Word

* "The answer is Java. What is the Question?"

h1. Java != A Dirty Word

!jruby-javapie.png!

h1. Java != A Dirty Word

* Fantastic Virtual Machine
** Tuned for over a decade by an army
** Runs on virtually all os/hardware combos
** Dynamic optimizations (Hotspot)
** Keeps getting faster:

|         | Java 5 | Java 6  |     |
| Rexml   | 10.9s  | 7.41s   | %32 |
| Hpricot |  4.06s | 2.59s   | %36 |

h1. Java != A Dirty Word

* Fantastic Garbage Collectors
** Compacting
** Concurrent
** Many tunables and choices

h1. Java != A Dirty Word

* Native threading
* Tools
** IDEs (refactoring, debugging)
** Profilers (instrumenting, sampling)
** JMX (ask VM for stats)
* Libraries
** Anything you can think of...
** Write image_science in 60 lines of Ruby using Java 2D

h1. Where is JRuby being used?

* Swing GUI development
** Makes Swing much nicer to use, easier to handle
* Ruby on Rails
** Better deployment options, better performance
* Tooling for IDEs
** JRuby's parser enables NetBeans, Eclipse, IntelliJ
* Graphics
** Ruby + Processing = cool demos

h1. Swing GUI Programming

* Swing API is very large, complex
** Ruby magic simplifies most of the tricky bits
* Java is a very verbose language
** Ruby makes Swing actually fun
* No consistent cross-platform GUI library for Ruby
** Swing works everywhere Java does (everywhere)
* No fire-and-forget execution
** No dependencies: any script works on any JRuby install

DEMO: Swing in Ruby

h1. Option 1: Direct approach

{{{
import javax.swing.JFrame
import javax.swing.JButton

frame = JFrame.new("Swing is easy now!")
frame.set_size 300, 300
frame.always_on_top = true

button = JButton.new("Press me!")
button.add_action_listener do |evt|
  evt.source.text = "Don't press me again!"
  evt.source.enabled = false
end

frame.add(button)
frame.show
}}}


h1. Option 2: Cheri (builder approach)

{{{
include Cheri::Swing

frame = swing.frame("Swing builders!") { |form|
  size 300, 300
  box_layout form, :Y_AXIS
  content_pane { background :WHITE }
  
  button("Event binding is nice") { |btn|
    on_click { btn.text = "You clicked me!" }
  }
}

frame.visible = true
}}}

h1. Option 3: Profligacy (targeted fixes)

{{{
class ProfligacyDemo
  import javax.swing.*
  include Profligacy

  def initialize
    layout = "[<translate][*input][>result]"
    @ui = Swing::LEL.new(JFrame, layout) {|cmps, ints|
      cmps.translate = JButton.new("Translate")
      cmps.input = JTextField.new
      cmps.result = JLabel.new

      translator = proc {|id, evt|
        original = @ui.input.text
        translation = MyTranslator.translate(original)
        @ui.result.text = translation
      }
      
      ints.translate = {:action => translator}
    }
  end
end
}}}

h1. Option 4: MonkeyBars (tool-friendly)

* GUI editor friendly (e.g. NetBeans "Matisse")
* Simple Ruby MVC-based API
* Combines best of both worlds

MonkeyBars Controller:

{{{
class RssController < Monkeybars::Controller
  set_view "RssView"
  set_model "RssModel"

  close_action :exit
  add_listener :type => :mouse, :components => ["goButton", "articleList"]

  def go_button_mouse_released(view_state, event)
    model.feed_url = view_state.feed_url
    content = Kernel.open(model.feed_url).read
    @rss = RSS::Parser.parse(content, false)

    model.articles = @rss.items.map {|art| art.title}
    model.article_text = CGI.unescapeHTML(@rss.items[0].description)
    update_view
  end
  ...
}}}

h1. Web applications

* Classic Java web dev is too complicated
** Modern frameworks follow Rails' lead
* Over-flexible, over-configured
** Conventions trump repetition and configuration
* Rails deployment is still a pain
** You shouldn't need N processes!
* Rails performance should be better
** JRuby has potential to be much faster

DEMO: GlassFish Gem

h1. Production JRuby on Rails

* Oracle's Mix – digg-like social customer site
** "mix.oracle.com":http://mix.oracle.com
* Sun's MediaCast – file distribution portal
** "mediacast.sun.com":http://mediacast.sun.com
* ThoughtWorks' Mingle – collaborative project mgmt
** "mingle.thoughtworks.com":http://mingle.thoughtworks.com
* Sonar – code/project analysis tool
** "sonar.hortis.ch":http://sonar.hortis.ch
* More on the way!


h1. JRuby Enables Tooling

* JRuby's parser used by most Ruby IDEs
** NetBeans Ruby Support
** Eclipse RDT/RadRails/Aptana, DLTK, 3rd Rail
** IntelliJ
** Jedit
* Roman Strobl's NetBeans session at 13:00

!jruby-tooling.png!

h1. Graphics with Processing

* "Processing is an open source programming language and environment for people who want to program images, animation, and interactions."
** Basically a cool Java library for 2D graphics
* Ruby-Processing wraps Processing with JRuby
** Cool, rubified 2D graphics environment for you
** Eye-candy demos for us
** Thanks to Jeremy Ashkenas for putting these together

DEMO: Pretty Graphics!

h1. Thank you!

* Main JRuby page: "www.jruby.org":http://www.jruby.org
* JRuby Wiki: "wiki.jruby.org":http://wiki.jruby.org
* Charles Nutter
** charles.nutter AT sun.com
** "headius.blogspot.com":http://headius.blogspot.com
* Tom Enebo
** thomas.enebo AT sun.com
** "www.bloglines.com/blog/ThomasEEnebo":http://www.bloglines.com/blog/ThomasEEnebo