PRDC11-Jruby-ironruby

(track sponsor)

Amir Barylko

Jruby &Iron Ruby

Monday, June 13, 2011

Amir Barylko - Jruby & Iron Ruby MavenThought Inc.

AMIR BARYLKOJRUBY & IRON RUBY

PRAIRIE DEV CONJUN 2011



WHO AM I?

• Architect

• Developer

•Mentor

• Great cook

• The one who’s entertaining you for the next while!



CONTACT AND MATERIALS

• Contact me: [email protected], @abarylko

• Blog:http://www.orthocoders.com

• Site:http://www.maventhought.com

• Download: http://www.orthocoders.com/presentations.



RUBY INTRODynamic languages

ToolboxFeatures



DYNAMIC LANGUAGES

High level

Dynamically typed

Runtime over compile time

Closures

Reflection

Platform independent



DEVELOPERS TOOLBOX

•Make your toolbox grow!

• The right tool for the job

• Not a replacement

• Combine strengths

• Problem solving



WELCOME TO RUBY

Created in mid-90s by “Matz” Matsumoto in Japan

Smalltalk, Perl influences

Dynamic typing

Object Oriented

Automatic memory management

Several implementations: MRI, YARB, JRuby

Totally free!!



RUBY FEATURES

Everything is an expression

Metaprogramming

Closures

Garbage collection

Exceptions

Operator overloading, flexible syntax

Powerful standard library



RUBY SUPPORT

Hundreds of books

User conferences all over the world

Active community (you can create a conference in your own city and top Ruby coders will go there to teach others, invite them and see)

Lots of great web sites: basecamp, twitter, 43 things, hulu, scribd, slideshare, Justin.tv

Lots of web frameworks inspired by Ruby on Rails



RUBY LANGUAGEBasic Types

Control StructuresMethodsModifiers



BASIC TYPES

Numbers

1.class => Fixnum

1.1.class => Float

(120**100).class => Bignum

3.times {puts “he “}



BASIC TYPES II

• Strings

'he ' + 'he' => he he

“That's right” => That's right

'He said “hi”' => He said “hi”

“He said \“hi\”” => He said “hi”

“1 + 1 is #{1+1}” => 1 + 1 is 2

"#{'Ho! '*3}Merry Christmas" =>Ho! Ho! Ho! Merry

Christmas



BASIC TYPES III

Arrays

a = [1, 5.5, “nice!”]

1 == a.first

1 == a[0]

nil == a[10]

a[1] = 3.14

a.each {|elem| puts elem}

a.sort



BASIC TYPES IV

• Hashesh = {“one” => 1, 1 => “one”}

h[“one”] == 1

h[1] == “one”

h[“two”] == nil

h.keys == [“one”, 1] (or is it [1, “one”] ?)

h.values == [“one”, 1] (or is it [1, “one”] ?)

h[“one”] = 1.0



BASIC TYPES V

Symbols: constant names. No need to declare, guaranteed uniqueness, fast comparison

:apple == :apple

:orange != :banana

[:all, :those, :symbols]

{:ca => “Canada”, :ar => “Argentina”, :es => “Spain”}



CONTROL STRUCTURES

if

while

if count < 20 puts “need more”elsif count < 40 puts “perfect”else puts “too many”end

while count < 100 && need_more buy(1)end



CONTROL STRUCTURES II

Statement modifiers

buy while need_more?

buy(5) if need_more?

buy until left == 0

buy unless left < 5



CONTROL STRUCTURES III

• Case

case left

when 0..5

dont_buy_more

when 6..10

buy(1)

when 10..100

buy(5)

end



METHODS

Simple

Default arguments

def play(movie_path)....end

def play(movie_path, auto_start = true, wrap = false)....end



METHODS II

Return value: the last expression evaluated, no need for explicit return

No need for parenthesis on call without arguments (same syntax to call a method and a field)

def votes(voted, num_votes) voted && num_votes || nilend

buy() == buy

movie.play() == movie.play



METHODS III

No need also with arguments (but careful!! only if you know what you are doing)

movie.play “Pulp fiction”, false, true



RUBY LANGUAGE IIClassesMixin

Enumerable



CLASSES & OBJECTS

Initializer and instance variablesclass Movie def initialize(name) @name = name end

def play puts %Q{Playing “#{@name}”. Enjoy!} endend

m = Movie.new(“Pulp fiction”)m.play

=> Playing “Pulp fiction”. Enjoy!



CLASSES & OBJECTS II Attributesclass Movie def initialize(name) @name = name end

def name @name end

def name=(value) @name = value end

end

m = Movie.new('Brazil').name = “Pulp fiction”

# attr_reader :name

# attr_writter :name

# attr_accessor :name}



CODE ORGANIZATION

Code in files with .rb extension

Require 'movie' will read movie.rb file and make its methods available to the current file

Require 'media/movie' will read file from media dir relative to the current working dir$LOAD_PATH << 'media'require 'movie'



CODE ORGANIZATION II

Relative to this file:require File.join(File.dirname(__FILE__), 'media/movie')



MIXINS

What about module “instance methods”?

One of the greatest Ruby features!

You can define functions in Modules, and get them added to your classes.

Great code reuse,

Multiple inheritance alternative.

Code organization



ENUMERABLE

Enumerable mixin, from the standard library documentation:

The Enumerable mixin provides collection

classes with several traversal and

searching methods, and with the ability to

sort. The class must provide a method each,

which yields successive members of the

collection



ENUMERABLE II

It provides useful methods such as:

map

to_a

take_while

count

inject



EXAMPLESrSpec

EnumerableMethod Missing

SinatraBDD Cucumber

DSL



RSPEC TESTING LIBRARY

require 'java'require 'rubygems'

java_import 'MovieLibrary'java_import 'Movie'

describe MovieLibrary do

it "should be created empty" do lib = MovieLibrary.new lib.contents.should be_empty end it "should add an element" do lib = MovieLibrary.new m = Movie.new 'Blazing Saddles' lib.add m lib.contents.should include(m) lib.contents.count.should == 1 end end



ENUMERBLE MIXIN

require 'rubygems'java_import 'MovieLibrary'java_import 'Movie'

class MovieLibrary include Enumerable def each(&block) contents.each(&block) endend



ENUMERBLE MIXIN

lib = MovieLibrary.new

lib.add(Movie.new "Blazing Saddles")lib.add(Movie.new "Spaceballs")lib.add(Movie.new "Young Frankenstein")

lib.each { |m| puts "The movie is #{m.title}"}

puts "\n\n**** Using Inject"lib.inject([]) { |a, m| a << m.title } .each { |s| puts "The movie is #{s}" }

puts "\n\n*** Using find"lib.find_all { |m| m.title.end_with? 's' } .each { |m| puts "The movies that end with s: #{m.title}"}



EXTEND LIBRARYWITH METHOD MISSING

require File.dirname(__FILE__) + "....bin/Debug/MavenThought.MovieLibrary.dll"require 'rubygems'include MavenThought::MovieLibrary

class Library def method_missing(m, *args) if m.id2name.include?("find_by") field = m.id2name.sub( /find_by_/, "") contents.find_all( lambda { |m| m.send(field) == args[0] } ) else super end end end

lib = Library.new

lib.add Movie.new( "Blazing Saddles", System::DateTime.new(1972, 1, 1))lib.add Movie.new( "Spaceballs", System::DateTime.new(1987, 1, 1))

puts "Using find by title #{lib.find_by_title( "Blazing Saddles" )}"



SIMPLE WEB WITH SINATRA

require 'rubygems'require 'sinatra'require 'haml'require 'singleton'

java_import 'MovieLibrary'java_import 'Movie'

class MovieLibrary include Singletonend

# indexget '/' do @movies = MovieLibrary.instance.contents haml :indexend

# createpost '/' do m = Movie.new(params[:title]) MovieLibrary.instance.add m redirect '/'end



BDD WITH CUCUMBER

Feature: Addition In order to make my library grow As a registered user I want to add movies to the library

Scenario: Add a movie Given I have an empty library When I add the following movies: | title | release_date | | Blazing Saddles | Feb 7, 1974 | | Young Frankenstein | Dec 15, 1974 | | Spaceballs | Jun 24, 1987 | Then The library should have 3 movies And "Blazing Saddles" should be in the list with date "Feb 7, 1974" And "Young Frankenstein" should be in the list with date "Dec 15, 1974" And "Spaceballs" should be in the list with release date "Jun 24, 1987"



BDD WITH CUCUMBER

require File.dirname(__FILE__) + "...MavenThought.MovieLibrary.dll"

include MavenThought::MovieLibrary

Given /^I have an empty library$/ do @lib = Library.newend

When /^I add the following movies:$/ do |table| table.hashes.each do |row| movie = Movie.new row[:title], System::DateTime.parse(...) @lib.add movie endend



DSL IRAKE

desc "Builds the project"task :build do call_target msbuild_cmd, :buildend

desc "Rebuild the application by cleaning and then building"task :rebuild => [:clean, :build]

desc "Runs all the tests"task :test => ["test:all"]



DSL IICRON - WHENEVER

every 10.minutes do runner "MyModel.some_process" rake "my:rake:task" command "/usr/bin/my_great_command" end

every 2.days, :at => '4:30am' do command "/usr/bin/my_great_command" end


QUESTIONS?

(Don’t be shy)



CONTACT AND MATERIALS

• Contact me: [email protected], @abarylko

• Blog:http://www.orthocoders.com

• Site:http://www.maventhought.com

• Download: http://www.orthocoders.com/presentations.



ONLINE RESOURCES

IronRuby: http://ironruby.net/

Jruby: http://jruby.org

Ruby language site: http://www.ruby-lang.org

rSpec: http://rspec.info/

Sinatra: http://www.sinatrarb.com/

Cucumber: http://cukes.info/

Rake: http://rake.rubyforge.org/


Technology

PRDC11-Jruby-ironruby