From java to rails

From Java...to Rails

Nick Sieger@nicksieger

?Are you happy with

your development pace

How do you get to a place where it’s better?

?

Introduce Language

Replace JSF with *Anything*

throw away

Built environmentlong-running projectswith legacy codebases

Sagrada Família, Barcelona, Spain

nativityfacade

passionfacade

scaffolded interior

Ryugyong Hotel,North Korea2004 2011

seismic retrofit

Szkieletor,Kraków, Poland

Metaphor Use Ruby, JRuby, and Rails to...

Sagrada Familia

• Build new facade faster• Scaffolding during refactoring

Ryugyong Hotel

• Revive a project with a new face

Seismic retrofit

• Reinforce business rules with a DSL• Harden security

Szkieletor • Find novel uses for abandoned code

Biological evolutionnew replaces old over time

Strangler Fig

github.com/nicksieger/refactoring-to-rails

Before we begin...

Test PlanDon’t leave home without it

gembundler.com

Bundler

source :rubygems

group :test do gem 'rspec-rails' gem 'cucumber-rails' gem 'capybara'end

Foot in the doorSneaking Ruby in

JRuby-Rackorg.jruby.rack:jruby-rack

App

/* /rack/*

Java RubyServlet

<listener> <listener-class> org.jruby.rack.RackServletContextListener </listener-class></listener>

<servlet> <servlet-name>rack</servlet-name> <servlet-class>org.jruby.rack.RackServlet</servlet-class></servlet>

<servlet-mapping> <servlet-name>rack</servlet-name> <url-pattern>/rack/*</url-pattern></servlet-mapping>

# WEB-INF/config.rurequire 'sinatra'

if development? require 'sinatra/reloader' use Rack::ShowExceptionsend

require 'app'

set :run, falserun Sinatra::Application

# app.rbget '/rack/' do '<h1>Sinatra</h1>'end

RESTNot just APIs...

URIs + HREFsArchitecture of the Web

<jruby-rack:rails path="/rack/vets" params="layout=none"/>

In JSPs

Red Green RefactorContinuous improvement

Interceptor patternPartial strangulation

App

/vets /owners/ /owners/1/pets

Filter

Java/Spring

App

/vets /owners/ /owners/1/pets

Filter

/vets/

Java/Spring

Ruby

SpringPetclinic::Application.routes.draw do

root :to => "welcome#index"

resources :vets

end

Request Rails response

Java response

/ 200 OK (N/A)

/owners404 Not Found

200 OK

Re-use viewsJSP-in-ERB

<%= request.render '/WEB-INF/jsp/header.jsp' %>

<%= yield %>

<%= request.render '/WEB-INF/jsp/footer.jsp' %>

Re-use modelsHibernate + ActiveModel

# app/models/owner.rbjava_import org.springframework.samples.petclinic.Owner


class Owner extend ActiveModel::Naming include ActiveModel::Validations include ActiveModel::Conversion

end


class Owner extend ActiveModel::Naming include ActiveModel::Validations include ActiveModel::Conversion

end

validates_presence_of :first_name, :last_name, :address, :city, :telephone validates_format_of :telephone, :with => /[-0-9.+ ]+/, :message => "..."

<%# app/views/owner/_form.html.erb %><%= form_for @owner do |f| %>

<%= f.label :first_name %> <br/> <%= f.text_field :first_name %>

<%= f.label :last_name %> <br/> <%= f.text_field :last_name %>

<%# ... %><% end -%>

<%# app/views/owner/_form.html.erb %><%= form_for @owner do |f| %>

<%= f.label :first_name %> <br/> <%= f.text_field :first_name %>

<%= f.label :last_name %> <br/> <%= f.text_field :last_name %>

<%# ... %><% end -%>

@owner

Rails takes overFinal strangulation

$ rails new petclinic --skip-active-record

$ mvn org.jruby.plugins:jruby-rake-plugin:classpath

# config/initializers/classpath.rbmodule Maven extend self

CLASSPATH = [ "#{BASEDIR}/target/classes", "#{ENV['HOME']}/.m2/.../org.springframework.core-3.0.0.RELEASE.jar", # lots of jars here... ]

def set_classpath require 'java' CLASSPATH.each {|p| $CLASSPATH << p } endend

Maven.set_classpath

module Spring SPRING_XML_CONFIG_FILES = [ 'classpath:applicationContext.xml' ].to_java :string # creates a String[]

CONTEXT = ClassPathXmlApplicationContext.new( SPRING_XML_CONFIG_FILES)end

INSTALL

Warblergem install warbler

# config/warble.rbWarbler::Config.new do |config|

require 'config/initializers/classpath' config.java_libs += Maven.jar_files

config.java_classes = FileList["target/classes/**/*"]

end

$ warble executable warCreating refactoring-to-rails.war$ java -jar refactoring-to-rails.war

Hollow out the tree

JRuby T-Shirts!Stop by booth #5605

Party Tue 6:30pm http://ey.io/oeuot1

http://ey.io/oeuot1

http://ey.io/oeuot1

➡ Script BowlNic WilliamsWed 8:30 AM–Hilton Grand Ballroom B

➡ Accelerate Your Business and Aim for the Cloud with Java and JRuby

Jacob Lehrbaum, Mike PiechWed 3:00 PM–Parc 55 Embarcadero

➡ Real World JRubyCharles Nutter, Thomas EneboWed 4:30 PM–Parc 55 Market Street

http://www.flickr.com/photos/john_mcclumpha/4138419594/http://www.flickr.com/photos/phil_shirley/4500893932/http://www.flickr.com/photos/y_i/2330044065/http://www.flickr.com/photos/herzogbr/462383777/http://en.wikipedia.org/wiki/File:Sagrada_Familia_01.jpghttp://www.flickr.com/photos/koocheekoo/38407225/http://www.flickr.com/photos/27649557@N07/5000528445/http://www.flickr.com/photos/gpaumier/446059442/http://www.flickr.com/photos/ilm/12831049/http://upload.wikimedia.org/wikipedia/commons/9/95/Ryugyong_hotel_01.jpghttp://upload.wikimedia.org/wikipedia/commons/7/78/Ryugyeong_Hotel_on_February_2011.jpghttp://en.wikipedia.org/wiki/File:ExteiorShearTruss.jpghttp://en.wikipedia.org/wiki/File:ExtReenfDetail.jpghttp://en.wikipedia.org/wiki/File:Szkieleteor_in_krakow.JPGhttp://www.flickr.com/photos/epingchris/5110376533/http://www.flickr.com/photos/bazylek/3194294047/http://www.flickr.com/photos/58847482@N03/5920653295/http://www.flickr.com/photos/nancybaym/3828905896/http://www.flickr.com/photos/anitagould/5501316782/

Images

http://www.flickr.com/photos/ilm/12831049/

http://www.flickr.com/photos/ilm/12831049/

http://en.wikipedia.org/wiki/File:ExtReenfDetail.jpg

http://en.wikipedia.org/wiki/File:ExtReenfDetail.jpg

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