jaoo michael neale 09

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JBoss Rules, RailsJAOO, Australia, 2009Sydney, Brisbane

Michael NealeJBoss R&DRed Hat Middleware

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Michael NealeR&D on Drools (rule engine).Open source history (user -> fulltime

developer).Contribute to other jboss and non jboss

projectsme on the web:

www.michaelneale.net, twitter.com/michaelneale, michaelneale.blogspot.com

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Agenda

•Doing more with less...

•But isn't java hard/slow?

•Quick introduction to Rails basics

•Setting up JBoss for Rails

•What are rules and why use them?

•Drools

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More, with lessDoes any one need to:

Build apps of growing complexityDo it quicker and cheaperCope with people changing their mindAll the timeAt runtime

If not – you can go !

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Drools:Logic and declarative programming for

developersUser friendly GUIs and management

tools for the restAllows controlled changes to business

logic (even at runtime)

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RailsPopular RESTful web-app framework

(full stack)Runs just fine on the JVMFamous for productivity

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Why the JVM?

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Its the platform..Not the language !

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A fan...

Oh that reminds me, twitter?

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Languages

RubyScala **GroovyClojureJava7????

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So not necessarily...Big heavy and bloatedBut it is a platform...

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Introduction to Ruby-on-Rails

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What is Rails?Rails is a “lightweight” MVC framework for building websites in Ruby.

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Rails MVC

•ActiveRecord for the models

•ERb templates for the view

•Simple ruby classes for the controllers

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ActiveRecord

Definitely is not Hibernate, but works well-enough.

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ActiveRecordclass Comment < ActiveRecord::Base

belongs_to :post belongs_to :user

validate_presence_of :text ...

end

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ERb Templates

ERb allows snippets of Ruby to be embedded within HTML or other templates.

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ERb Templates<p>There are <%= @post.comments.size %> new comments since your last visit:</p>

<% for comment in @post.comments %> <% div_for( comment ) do %> <%= comment.author.full_name %> <% end %><% end %>

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ActionControllerYour ActionController sub-classes provides the logic behind the pages and forms.

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ActionControllerclass CommentsController < ApplicationController

before_filter :load_post

def create @comment = @post.comments.build( params[:comment] ) .... end

private

def load_post @post = Post.find_by_slug( params[:slug] ) redirect_to posts_url and return false unless @post endend

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ActionControllerclass CommentsController < ApplicationController

before_filter :load_post

def create @comment = @post.comments.build( params[:comment] ) .... end

private

def load_post @post = Post.find_by_slug( params[:slug] ) redirect_to posts_url and return false unless @post endend

Actions

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ActionControllerclass CommentsController < ApplicationController

before_filter :load_post

def create @comment = @post.comments.build( params[:comment] ) .... end

private

def load_post @post = Post.find_by_slug( params[:slug] ) redirect_to posts_url and return false unless @post endend

Filters

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Where’s the Java?JRuby is a full and fast Ruby interpreter built on top of the Java Virtual Machine.

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JRubyJRuby is actively developed by Charlie Nutter, Thomas Enebo, and others.

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Run Rails in the JVMAfter solving a few issues, Rails runs easily within most any servlet container.

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Why JBoss, then?

•JBoss provides a perfectly nice servlet container.

•JBoss provides a whole lot more, too:

•JMS•Transactions•Rules-Engine•Telecom

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Rails is not enoughRails is a great solution...

for the web.

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Beyond RailsApply the Ruby and Rails philosophies to enterprise-grade services.

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Ruby is just a syntaxApproach Ruby as just another syntax for driving JEE/JVM technologies.

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Let’s get started.

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IngredientsJDK6JBoss AS5JRubyRailsJBoss-Rails

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JDK6

•OpenJDK is very nice.

•Apple’s JDK6 works just fine.

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Install JBoss AS5.x

$ unzip jboss-5.0.1.GA-jdk6.zip Archive: jboss-5.0.1.GA-jdk6.zip creating: jboss-5.0.1.GA/ creating: jboss-5.0.1.GA/bin/ ...

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Set $JBOSS_HOME

$ cd jboss-5.0.1.GA

$ export JBOSS_HOME=$PWD

$ echo $JBOSS_HOME/Users/mic/jboss-5.0.1.GA

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Install JRuby

$ unzip jruby-bin-1.2.0RC2.zip Archive: jruby-bin-1.2.0RC2.zip creating: jruby-1.2.0RC2/ creating: jruby-1.2.0RC2/bin/ ...

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Prefer JRuby

$ cd jruby-1.2.0RC2/$ export JRUBY_HOME=$PWD$ export PATH=$JRUBY_HOME/bin:$PATH

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JRuby pathThis pulls things like rake and gem from JRuby’s path instead of C-Ruby’s.

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JBoss-Rails

The first part of JBoss-Rails is the deployer.

The Deployer

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JBoss-Rails

The deployer makes JBoss AS5 Rails-aware.

The Deployer

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JBoss-Rails

Install it into the server’s deployers/ directory

The Deployer

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Pick a Profile

AS5 provides several configuration profiles.

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The default profile

$JBOSS_HOME/server/default/

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Drop in the deployer

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(or copy it)

$ cp jboss-rails-deployer.jar \ $JBOSS_HOME/server/default/deployers/

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Remove ROOT.war

$ rm -Rf $JBOSS_HOME/server/*/deploy/ROOT.war/

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JBoss-Rails

The second part of JBoss-Rails is application-support library.

jboss-rails-support

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JBoss-Rails

It goes right into your Rails app.

So we need a Rails app.

jboss-rails-support

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Install Rails

$ gem install rails --version 2.2.2Successfully installed activesupport-2.2.2Successfully installed activerecord-2.2.2Successfully installed actionpack-2.2.2Successfully installed actionmailer-2.2.2Successfully installed activeresource-2.2.2Successfully installed rails-2.2.26 gems installed

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Create an app$ rails twiggl create create app/controllers create app/helpers create app/models create app/views/layouts create config/environments create config/initializers create config/locales ...

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Freeze Rails$ rake rails:freeze:gemsFreezing to the gems for Rails 2.2.2rm -rf vendor/railsmkdir -p vendor/railscd vendor/railsUnpacked gem: '/Users/bob/twiggl/vendor/rails/activesupport-2.2.2'mv activesupport-2.2.2 activesupportUnpacked gem: '/Users/bob/twiggl/vendor/rails/activerecord-2.2.2'mv activerecord-2.2.2 activerecordUnpacked gem: '/Users/bob/twiggl/vendor/rails/actionpack-2.2.2'mv actionpack-2.2.2 actionpackUnpacked gem: '/Users/bob/twiggl/vendor/rails/actionmailer-2.2.2'mv actionmailer-2.2.2 actionmailerUnpacked gem: '/Users/bob/twiggl/vendor/rails/activeresource-2.2.2'mv activeresource-2.2.2 activeresourceUnpacked gem: '/Users/bob/twiggl/vendor/rails/rails-2.2.2'cd -

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Why freeze?Relying on system-wide gems is a bad idea, and impossible with JBoss-Rails.

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JBoss-Rails

Now we can install the application-support library.

jboss-rails-support

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JBoss-Rails$ cd vendor/plugins/$ unzip ~/downloads/jboss-rails-support.zipArchive: /Users/bob/downloads/jboss-rails-support.zip creating: jboss-rails-support/ creating: jboss-rails-support/lib/ creating: jboss-rails-support/lib/jboss/ creating: jboss-rails-support/lib/jboss/endpoints/ creating: jboss-rails-support/lib/jboss/jobs/ creating: jboss-rails-support/lib/recipes/ creating: jboss-rails-support/lib/tasks/ inflating: jboss-rails-support/init.rb .....

jboss-rails-support

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Apps need a database.

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PostgresSQL

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Create the DB stuff

postgres> create user twiggl with password 'twiggl';CREATE ROLEpostgres> create database twiggl_development with owner twiggl encoding 'UTF8';CREATE DATABASE

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Set up your app

development: adapter: postgresql database: twiggl_development username: twiggl password: twiggl host: localhost encoding: UTF8

config/database.yml

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Set up your app

development: adapter: postgresql database: twiggl_development username: twiggl password: twiggl host: localhost encoding: UTF8

config/database.yml

Just likeregular Rails!

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Database access

Rails on JBoss can take advantage of JDBC drivers.

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Easy JDBCThe jboss-rails-support library makes it easy to set up your Rails app for JDBC.

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Install the JDBC gems$ rake jboss:gems:jdbc:install

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Install the JDBC gems$ rake jboss:gems:jdbc:installINFO: Installing activerecord-jdbc adapter-0.8.3

activerecord-jdbc

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Install the JDBC gems the result

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You’re ready!

•AS5 is ready to serve Rails apps.

•A bare database is setup.

•A bare Rails app is setup.

•Configured to access the database.

•Using JDBC.

•Extra JBoss goodness is installed.

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Deploying a Rails AppThe jboss-rails-support rake tasks handle deploying and undeploying.

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From your app

$ rake jboss:rails:deployDeployed twiggl

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Deployment Descriptor

application: RAILS_ENV: development RAILS_ROOT: /Users/bob/twigglweb: context: /

$JBOSS_HOME/server/default/deploy/twiggl-rails.yml

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Wait, AS isn’t running!

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Start AS$ rake jboss:as:run(in /Users/bob/twiggl)JBoss-Rails server: /Users/bob/jboss-5.0.1.GA/server/default=========================================================================

JBoss Bootstrap Environment

JBOSS_HOME: /Users/bob/jboss-5.0.1.GA

JAVA: /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home//bin/java

JAVA_OPTS: -Dprogram.name=run.sh -Xms128m -Xmx512m -XX:MaxPermSize=256m -Dorg.jboss.resolver.warning=true -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000

CLASSPATH: /Users/bob/preso/jboss-5.0.1.GA/bin/run.jar

=========================================================================

13:44:45,281 INFO [ServerImpl] Starting JBoss (Microcontainer)...13:44:45,283 INFO [ServerImpl] Release ID: JBoss [Morpheus] 5.0.1.GA (build: SVNTag=JBoss_5_0_1_GA date=200902232048)13:44:45,283 INFO [ServerImpl] Bootstrap URL: null13:44:45,283 INFO [ServerImpl] Home Dir: /Users/bob/jboss-5.0.1.GA13:44:45,283 INFO [ServerImpl] Home URL: file:/Users/bob/jboss-5.0.1.GA/13:44:45,287 INFO [ServerImpl] Library URL: file:/Users/bob/jboss-5.0.1.GA/lib/13:44:45,288 INFO [ServerImpl] Patch URL: null13:44:45,288 INFO [ServerImpl] Common Base URL: fi le:/Users/bob/jboss-5.0.1.GA/common/13:44:45,288 INFO [ServerImpl] Common Library URL: file:/Users/bob/jboss-5.0.1.GA/common/lib/13:44:45,288 INFO [ServerImpl] Server Name: default13:44:45,289 INFO [ServerImpl] Server Base Dir: /Users/bob/jboss-5.0.1.GA/server13:44:45,289 INFO [ServerImpl] Server Base URL: file:/Users/bob/jboss-5.0.1.GA/server/13:44:45,289 INFO [ServerImpl] Server Config URL: file:/Users/bob/jboss-5.0.1.GA/server/default/conf/13:44:45,289 INFO [ServerImpl] Server Home Dir: /Users/bob/jboss-5.0.1.GA/server/default13:44:45,289 INFO [ServerImpl] Server Home URL: file:/Users/bob/jboss-5.0.1.GA/server/default/

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localhost:8080/index.html

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Create models$ jruby ./script/generate resource twig

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Create models$ jruby ./script/generate resource twig ... create app/models/twig.rb

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Create models$ jruby ./script/generate resource twig ... create app/models/twig.rb ... create db/migrate/20090308180254_create_twigs.rb

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Create models$ jruby ./script/generate resource twig ... create app/models/twig.rb ... create db/migrate/20090308180254_create_twigs.rb ... create app/controllers/twigs_controller.rb

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Create models$ jruby ./script/generate resource twig ... create app/models/twig.rb ... create db/migrate/20090308180254_create_twigs.rb ... create app/controllers/twigs_controller.rb ... route map.resources :twigs

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Create models

class CreateTwigs < ActiveRecord::Migration def self.up create_table :twigs do |t| t.string :name, :limit=>42, :null=>false t.timestamps end end

def self.down drop_table :twigs endend

db/migrate/*_create_twigs.rb

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Blow it into the DB

$ rake db:migrate(in /Users/bob/twiggl)== CreateTwigs: migrating ===============-- create_table(:twigs) -> 0.0669s -> 0 rows== CreateTwigs: migrated (0.0683s) ======

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Rough in a controller

class TwigsController < ApplicationController

def index @twigs = Twig.find( :all ) end end

app/controllers/twigs_controller.rb

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Rough in a template

<p>There are <%= @twigs.size %> twigs.</p>

<% for twig in @twigs %> <% div_for( twig ) do %> <%= twig.name %> <% end %><% end %>

app/views/twigs/index.html.erb

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Rough in a template<p>There are <%= @twigs.size %> twigs.</p>

<% for twig in @twigs %> <% div_for( twig ) do %> <%= twig.name %> <% end %><% end %>

app/views/twigs/index.html.erb

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Rough in a template<p>There are <%= @twigs.size %> twigs.</p>

<% for twig in @twigs %> <% div_for( twig ) do %> <%= twig.name %> <% end %><% end %>

app/views/twigs/index.html.erb

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Hit it!

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We didn’t restart AS.And we didn’t redeploy our app, either. That’s okay, we’re hacking hot code.

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Twig managementclass TwigsController < ApplicationController

def new @twig = Twig.new end

def create @twig = Twig.create( params[:twig] ) redirect_to @twig end end

app/controllers/twigs_controller.rb

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Twig form

<% form_for @twig do %> <%= label :twig, :name %> <%= text_field :twig, :name %> <%= submit_tag 'Create twig!' %><% end %>

app/views/twigs/new.html.erb

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Twig management

class TwigsController < ApplicationController

def show @twig = Twig.find_by_id( params[:id] ) redirect_to twigs_url unless @twig end end

app/controllers/twigs_controller.rb

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Twig view

<% div_for @twig do %> <h1><%= @twig.name %></h1><% end %>

app/views/twigs/show.html.erb

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Create a twig

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Create a twig

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Back to the index

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It’s just like regular Rails.

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Beyond RailsBut, we have the entire freakin’ JBoss AS5 there.

Let’s use it.

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Job schedulingSometimes you need some code to fire on a recurring basis, outside of the web context.

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Job Scheduling

•Nightly batches

•Polling RSS

•Checking email

•Watching directories

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Jobsapp/jobs/**/*.rb

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class TwitterSender < JBoss::Jobs::BaseJob def run new_twigs = Twig.find( :all, :conditions=>[ 'created_at >= ?', Time.now - 30.minutes ] ) return if new_twigs.empty? tweet( new_twigs.size ) end

def tweet(num_new_twigs) .. end

end

Job classapp/jobs/twitter_sender.rb

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Job schedule

twitter.sender: description: Send a tweet cron: 0 */30 * * * ? job: TwitterSender

config/jobs.yml

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Job schedule

twitter.sender: description: Send a tweet cron: 0 */30 * * * ? job: TwitterSender

config/jobs.yml

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Job schedule

twitter.sender: description: Send a tweet cron: 0 */30 * * * ? job: TwitterSender

config/jobs.yml

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Job schedule

twitter.sender: description: Send a tweet cron: 0 */30 * * * ? job: TwitterSender

config/jobs.yml

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Job schedule

twitter.sender: description: Send a tweet cron: 0 */30 * * * ? job: TwitterSender

config/jobs.yml

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Redeploy the app

$ rake jboss:rails:deploy

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Why redeploy?Jobs are deployed when your app is deployed. Adding a job means you need to redeploy your app.

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Ta-da!

[RubyJob] Starting Ruby job: twiggl.twitter.sender

...

[STDOUT] twittering [1 new twigs!]

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Hot, hot codeOnce your job is deployed, you can continue to edit the actual service method.

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No further redeployment is necessary, unless you add jobs or alter the schedule.

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Some More Possibilities Message Queues (MQ/JMS)

Legacy/JCA integration

WS style web services...

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Ruby Databinding

JBoss-Rails provides automatic databinding to XMLSchema types.

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Ruby DatabindingWhen WS deployed, the WSDL is examined and real Ruby classes are created.

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Shifting gears...

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What are rules?

Business rules

Declarative statements

Logic/reasoning

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What are rules?

Capture domain expert knowledge as statements/assertions of truth (aka: business rules)

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What are rules?

An executable knowledge base

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DroolsDrools provides a runtime, compiler and tools to develop and manage executable knowledge bases

(all open source of course)

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For example:rule “age and history compliance” when Driver(age < 25, sex=”M”) not Accident(severity > 3) not Infringement(type==”dui”) then approveDriver(“Let this one through”)end

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For example:rule “age and history compliance” when Driver(age < 25, sex=”M”) not Accident(severity > 3) not Infringement(type==”dui”) then approveDriver(“Let this one through”)end

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For example:rule “age and history compliance” when Driver(age < 25, sex=”M”) not Accident(severity > 3) not Infringement(type==”dui”) then approveDriver(“Let this one through”)end

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For example:rule “age and history compliance” when Driver(age < 25, sex=”M”) not Accident(severity > 3) not Infringement(type==”dui”) then approveDriver(“Let this one through”)end

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For example:rule “age and history compliance” when Driver(age < 25, sex=”M”) not Accident(severity > 3) not Infringement(type==”dui”) then approveDriver(“Let this one through”)end

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For example:rule “age and history compliance” when Driver(age < 25, sex=”M”) not Accident(severity > 3) not Infringement(type==”dui”) then approveDriver(“Let this one through”)end

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For example:rule “age and history compliance” when Driver(age < 25, sex=”M”) not Accident(severity > 3) not Infringement(type==”dui”) then approveDriver(“Let this one through”)end

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Why?You have domain experts

The rules change

Anti-spaghetti

if else if else if else ...

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The Guvnor..

Repository and Web interface

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How?

In process on the JVM

As a decision service

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Where?Logistics (Fedex – talk at J1)

Insurance, risk, fraud etc..

All domains..

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Questions!For more info:

Contact me: http://twitter.com/michaelneale

http://oddthesis.org/theses/jboss-rails/projects/jboss-rails

http://jboss.org/drools