Why would a Java shop want to use Ruby?
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Why would a Java shop want to use Ruby?

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Briefly explores several practical reasons that may encourage Java shops to explore Ruby.

Briefly explores several practical reasons that may encourage Java shops to explore Ruby.

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    Why would a Java shop want to use Ruby? Why would a Java shop want to use Ruby? Presentation Transcript

    • Why would a Java Shop want to use Ruby? Keith Pitty Open Source Developers’ Conference Brisbane 29 November 2007
    • About Keith • Programming professionally since 1983 • Early experience on mainframes • Smalltalk was my first OO language • Employed by a Java consultancy since 2000 • Fascinated by Ruby and Rails since 2004 • Enjoy sampling a wide range of beers Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Java Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Java public class print { public static void main(String[] args) { System.out.println(quot;Hi, I'm Javaquot;); } } Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby #!/usr/bin/env ruby puts quot;Hi, I'm Rubyquot; Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • No!!! • This is not a language war! • Java and Ruby both have their strengths • I’m not interested in Ruby “beating” Java • The question is: • Can Ruby help Java programmers? Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Java • Most popular language (21.7%) • TIOBE PCI, September 2007 • Mature platform • Trusted in the “enterprise” • Has reached a plateau • “The new COBOL” Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby • Tenth most popular language (2.1%) • Marked increase in popularity since mid-2006 due to Ruby on Rails • Matz’s original motivation: • a scripting language • more powerful than Perl • more object-oriented than Python Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Why Ruby? (Quote Part 1) “I don’t believe there would be any real technical benefit. There may be a productivity boost, but when you consider how much time is used by developers, QA, etc... to bring in a new technology, chances are the net [benefit] won’t be that great.” Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Why Ruby? (Quote Part 2) “I think the best argument for Ruby is that your developers want it. If the developers are yearning for new technology, it’s probably worth considering. Happy developers code more and code better.” Norman Richards, JBoss Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Perspectives • Vendors • Open source contributors • Managers • Business owners • Developers Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby: Why not? • How widespread is knowledge of Ruby within the Java community? • In my experience, there is limited awareness • On the other hand: • Ruby may have benefits that are complementary to Java Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Potential Ruby Benefits • Ruby skills may complement Java skills • Learning Ruby may be interesting, broadening a programmer’s thinking • Happier programmers • Quicker time to market Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Enough Preamble • What does Ruby have to offer people in Java development shops? • Let’s explore some specifics... Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby Scripts Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby Scripts • Scripts help with repetitive tasks • Shell scripts, SQL scripts, Ant scripts • Sometimes the logic lends itself to a general purpose language • Can run a Java application via a shell script • A Ruby script is interpreted directly and is more concise Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby Script Example • Deleting files within a given directory according to given criteria • e.g. older than a given time Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby Script Example* #!/usr/bin/env ruby def delete_if(dir) Dir.chdir(dir) do Dir.foreach(*.*) do |entry| next if File.stat(entry).directory? if yield entry File.unlink(entry) end end end end delete_if(quot;/tmpquot;) { |f| File.mtime(f) < Time.local(2007,10,29,0,0,0) } * See Hal Fulton’s “The Ruby Way” Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Rake and Internal DSLs Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Rake • Ruby-based build language • Developed by Jim Weirach • Similar to make and ant • An internal Domain Specific Language • make and ant are external DSLs Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Regular Rake Tasks task :init do # init actions end task :compile => [:init] do # compile actions end task :build => [:init, :compile] do # build actions end Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Extending Rake* def copyTask srcGlob, targetDirSuffix, taskSymbol targetDir = File.join BUILD_DIR, targetDirSuffix mkdir_p targetDir, QUIET FileList[srcGlob].each do |f| target = File.join targetDir, File.basename(f) file target => [f] do |t| cp f, target end task taskSymbol => target end end copyTask 'articles/*.gif', 'articles', :articles * see Martin Fowler’s rake article Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Internal DSLs • Other Ruby internal DSLs: • buildr • capistrano • ... • create your own! Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Buildr • a build system for Java apps • encompasses Maven and Ant • written in Ruby • based on Rake • uses Antwrap to configure and run Ant tasks • extensible in Ruby Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Capistrano • Created by Jamis Buck • Originally to “ease the pain of deploying Rails applications” • Exposes simple commands • Once project has been “capified” • $ cap deploy • Useful beyond Rails Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Capistrano Example desc quot;Copy production database config file.quot; namespace :deploy do task :after_update_code, :roles => :app do db_config = quot;#{shared_path}/config/database.yml.productionquot; run quot;cp #{db_config} #{release_path}/config/database.ymlquot; end end Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Metaprogramming Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Metaprogramming • Very powerful feature of Ruby • Dynamic programming • Methods: method_missing, define_method, module_eval, class_eval, instance_eval, self.included, self.inherited, extend • Callable objects: procs, lambdas, blocks • Modifying the singleton class: class << Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • method_missing class Roman def roman_to_int(str) # ... end def method_missing(methId) str = methId.id2name roman_to_int(str) end end r = Roman.new r.iv #=> 4 r.xxiii #=> 23 r.mm #=> 2000 Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • More Examples? • Open source Ruby frameworks • e.g. Ruby on Rails web application framework • many examples of metaprogramming to be found in the Rails source code Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby on Rails Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Ruby on Rails • Web application framework released by David Heinemeier Hansson in 2004 • Extracted from the Basecamp application • The killer app for Ruby • “Convention over Configuration” • Code generators Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Rails Example $ rails beers Creates directory structure for new project Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Generating a Resource $ ./script/generate scaffold_resource beer name:string Creates a model, a controller, and a set of templates that's ready to use as the starting point for your REST-like, resource-oriented application. Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Migration class CreateBeers < ActiveRecord::Migration def self.up create_table :beers do |t| t.column :name, :string end end def self.down drop_table :beers end end Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Running Migrations $ rake db:migrate == CreateBeers: migrating ===================================================== -- create_table(:beers) -> 0.0735s == CreateBeers: migrated (0.0737s) ============================================ Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Model class Beer < ActiveRecord::Base has_many :votes end Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • View (new.rhtml) <h1>New beer</h1> <%= error_messages_for :beer %> <% form_for(:beer, :url => beers_path) do |f| %> <p> <b>Name</b><br /> <%= f.text_field :name %> </p> <p> <%= submit_tag quot;Createquot; %> </p> <% end %> <%= link_to 'Back', beers_path %> Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Controller class BeersController < ApplicationController def new @beer = Beer.new end def create @beer = Beer.new(params[:beer]) respond_to do |format| if @beer.save flash[:notice] = 'Beer was successfully created.' format.html { redirect_to beer_url(@beer) } else format.html { render :action => quot;newquot; } end end end end Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • More about Rails • There’s much more about Rails to explore • But that’s another topic • We’ve touched upon some appealing aspects • Development is much quicker! • But ... Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Java Perspective • What if ... • Java provides where Ruby doesn’t? • What about ... • deploying Rails apps? Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Java and Ruby Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • JRuby Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • JRuby • Java implementation of Ruby • Major advantages: • Java libraries can be used with Ruby syntax • Deploy Rails apps on Java app servers • via WAR files Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Invoking Java from Ruby require 'java' m = java.util.HashMap.new m.put quot;Streamquot;, quot;Rubyquot; m.put quot;Topicquot;, quot;JRubyquot; iter = m.keySet.iterator while iter.hasNext key = iter.next puts quot;#{key}=#{m.get(key)}quot; end Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Some JRuby Capabilities • Implement Java interfaces via import or impl • Extend Java classes • Use Ruby methods on Java collections courtesy of Ruby mixins • Use JavaUtilities.extend_proxy to add methods to Java types Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Java DOM and XSLT* require 'java' require 'stringio' TransformerFactory = javax.xml.transform.TransformerFactory StreamSource = javax.xml.transform.stream.StreamSource StreamResult = javax.xml.transform.stream.StreamResult f = TransformerFactory.new_instance t = f.new_transformer StreamSource.new(java.io.FileReader.new(ARGV[1])) s = StringIO.new t.transform StreamSource.new(java.io.FileReader.new(ARGV[0])), StreamResult.new(org.jruby.util.IOOutputStream.new(s)) puts s.string * see Ola Bini’s book Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • JRuby on Rails Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • JRuby on Rails: JDBC • Download JDBC driver development: adapter: jdbc driver: com.mysql.jdbc.Driver • Add to CLASSPATH url: jdbc:mysql://localhost/ beers_development username: test • password: test Configure config/ database.yml • Update config/ require 'jdbc_adapter' environment.rb Rails::Initializer.run do |config| Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Deploying JRuby on Rails Applications • Option 1: • Pack of Mongrels inside one JVM • Option 2: • Bundle as WAR and deploy inside Tomcat Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Pack of Mongrels • Familiar to Rails developers • Install mongrel_jcustler Gem • Configure pack using mongrel_rails • Start pack using mongrel_rails • Configure load balancing proxy support and virtual host in Apache Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Deploying via a WAR • Install GoldSpike plug-in in Rails app • Configure app with correct driver for JDBC connections (in config/war.rb) • Use jruby rake task to create WAR • Deploy WAR • Configure Apache Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Installing GoldSpike jruby script/plugin install -x svn://rubyforge.org/var/svn/jruby-extras/trunk/rails-integration/plugins/goldspike Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • JDBC Driver Config maven_library 'mysql', 'mysql-connector-java', '5.0.4' Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Create WAR jruby -S rake war:standalone:create Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Deploy WAR cp beers.war $TOMCAT_HOME/webapps Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Conclusion • Ruby offers some interesting benefits • Ruby on Rails offers quick development for CRUD web apps • JRuby enables Ruby apps to call Java code • JRuby enables deployment of Rails apps via WAR files to Java app servers Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Resources • Ola Bini. Practical JRuby on Rails Web 2.0 Projects. Apress, 2007 • David A. Black. Ruby for Rails. Manning, 2006 • http://buildr.rubyforge.org • http://www.capify.org • http://jruby.codehaus.org Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Resources (ctd.) • Martin Fowler. RailsConf2007 => http:// martinfowler.com/bliki/ RailsConf2007.html • Martin Fowler. Using the Rake Build Language => http://martinfowler.com/ articles/rake.html • Hal Fulton. The Ruby Way. Addison- Wesley, 2007 Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Resources (ctd) • David Heinemeier Hansson. Sun surprises at RailsConf Europe 2007 => http://www.loudthinking.com/ posts/11-sun-surprises-at-railsconf- europe-2007 • Brian Marick. Everyday Scripting with Ruby: For Teams, Testers and You. Pragmatic Programmers, 2006 Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Resources (ctd) • http://mongrel.rubyforge.org • Keith Pitty. Why is Ruby such a good language for Rails? => http:// keithpitty.org/presentations/ruby/ WhyRubyForRails.pdf • http://rubyonrails.org • http://www.tiobe.com/tpci.htm Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Photo Credits • Bored Cow: http://flickr.com/ photos/kevincollins/122302356/ • Leopard getting ready to drop out of tree: http://flickr.com/photos/ at_large/399149551/ • Origami heart: http://flickr.com/ photos/teagrrl/4802517/ Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007
    • Thanks for listening! http://keithpitty.com Why would a Java Shop want to use Ruby? Keith Pitty OSDC, 29 November 2007