This document discusses Ruby, an object-oriented scripting language, and its integration with Java via JRuby. It provides an overview of Ruby concepts like classes, modules, and metaprogramming. It then discusses how JRuby allows embedding Ruby as a scripting language in Java applications and using Java classes from Ruby. It also covers Ruby on Rails and how JRuby can be used to deploy Rails applications on the JVM. Finally, it discusses performance improvements in JRuby 1.7 and some benefits of using JRuby.

1. Programmer’s Best
Friend on JVM
Raimonds Simanovskis

2. @rsim
github.com/rsim
Raimonds Simanovskis

3. The easiest Business Intelligence tool on the Web

4. What is
Ruby?

5. object-oriented
dynamic
programming language
simple from outside
Yukihiro
Matsumoto
or “Matz”
powerful inside

6. Classes

7. Single Inheritance

8. Constructor

9. No Type Declarations

10. Instance Variables

11. Last expression is
always return value

12. .new is just a class method

13. Blocks / Closures
Anonymous function as argument

14. Modules

15. Metaprogramming

16. Classes/Modules are open

18. Integration with Java
Embed JRuby as
scripting engine
Use Java classes
from JRuby

19. Embed JRuby

20. Embed JRuby

21. Use Java classes
from JRuby
Demo

22. Build with Rake

23. Test with Test::Unit or RSpec

24. Test with Test::Unit or RSpec

25. Ruby on Rails
Web applications development framework
Model View Controller (MVC) architecture
Convention over Configuration
Don’t Repeat Yourself (DRY)
Focused on developer productivity
Agile software development approach

26. MVC Architecture
Request Router Database
SQL
Browser
Response
Action Active
Controller Record
Action
View

27. ActiveRecord (Model)
class CreatePosts < ActiveRecor::Migration
def self.up
create_table :posts do |t| CREATE TABLE posts (
t.string :title id NUMBER(38) NOT
t.text :body NULL,
t.timestamps title VARCHAR2(255),
end body CLOB,
end created_at DATE,
end updated_at DATE
);
CREATE SEQUENCE posts_seq;
class Post < ActiveRecord::Base
# nothing here!
end
post = Post.new
post.title = "First post"
post.save
post = Post.find(1)
puts post.name # output: "First post"

28. ActionController
class PostsController < ApplicationController
# GET /posts
def index
@posts = Post.all
end
# GET /posts/1
def show
@post = Post.find(params[:id])
end
# GET /posts/new
def new
@post = Post.new
end
# ...
end

29. ActionView
<h1>Posts</h1>
<% @posts.each do |post| %>
<h2><%= post.title %></h2>
<h3>Created at <%= post.created_at %></h3>
<p><%= post.body %></p>
<% end %>

30. JRuby deployment
<insert app server here>
Java app sever
Application WAR file
Application JRuby Gems
warbler
source Application

31. JRuby deployment
Web Server
Trinidad JRuby
Apache Tomcat
Gems
Application
deploy Application
source

32. JRuby deployment

33. eazyBI case study
.com
Ruby on Rails Jetty JRuby
application deploy
Application Gems
Mondrian OLAP engine
Apache Batik SVG toolkit
pac Private
kag
e
package
Packaged application
plugin
OSGi bundle Application Gems
JRuby jruby-rack *.jar
Application Gems
SQL Server

34. JRuby 1.7 and Java 7
invokedynamic

35. Ruby method calls

36. Ruby method calls

37. Ruby method calls

38. Ruby method calls

39. Ruby method calls

40. JRuby performance
improvements
JRuby/Java 6 JRuby/Java 7
Times Faster than Ruby 1.9.3
5
4.226 4.32
3.75
3.66
3.44
2.5 2.658
1.914 1.806
1.538 1.565
1.25 1.346
0
base64 richards neural mandelbrot redblack

41. JRuby Benefits
Easy to learn for Java programmers
Easy to mix Ruby and Java
Useful frameworks and libraries
Higher productivity for many tasks
Ruby community