JBoss
Rules, Rails
JAOO, Australia, 2009
Sydney, Brisbane
Michael Neale
JBoss R&D
Red Hat Middleware
1

Michael Neale
R&D on Drools (rule engine).
Open source history (user -> fulltime
developer).
Contribute to other jboss and non jboss
projects
me on the web:
www.michaelneale.net, twitter.com/michaelneale,
michaelneale.blogspot.com
2

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
3

More, with less
Does any one need to:
Build apps of growing complexity
Do it quicker and cheaper
Cope with people changing their mind
All the time
At runtime
If not – you can go !
4

Drools:
Logic and declarative programming for
developers
User friendly GUIs and management
tools for the rest
Allows controlled changes to business
logic (even at runtime)
5

Rails
Popular RESTful web-app framework
(full stack)
Runs just fine on the JVM
Famous for productivity
6

Why the JVM?
7

Its the platform..
Not the language !
8

9

A fan...
Oh that reminds me, twitter?
10

Languages
Ruby
Scala **
Groovy
Clojure
Java7????
11

So not necessarily...
Big heavy and bloated
But it is a platform...
12

Introduction to
Ruby-on-Rails
13

What is Rails?
Rails is a “lightweight”
MVC framework for
building websites in
Ruby.
14

Rails MVC
•ActiveRecord for the models
• ERb templates for the view
•Simple ruby classes for the
controllers
15

ActiveRecord
Definitely is not
Hibernate, but works
well-enough.
16

ActiveRecord
class Comment < ActiveRecord::Base
belongs_to :post
belongs_to :user
validate_presence_of :text
...
end
17

ERb Templates
ERb allows snippets of
Ruby to be embedded
within HTML or other
templates.
18

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 %>
19

ActionController
Your ActionController sub-
classes provides the logic
behind the pages and
forms.
20

ActionController
class 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
end
end
21

ActionController
Actions
class 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
end
end
22

ActionController
Filters
class 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
end
end
23

Where’s the Java?
JRuby is a full and fast
Ruby interpreter built on
top of the Java Virtual
Machine.
24

JRuby
JRuby is actively
developed by Charlie
Nutter, Thomas Enebo,
and others.
25

Run Rails in the
JVM
After solving a few
issues, Rails runs
easily within most any
servlet container.
26

Why JBoss, then?
•JBoss provides a perfectly nice servlet
container.
•JBoss provides a whole lot more, too:
•JMS
• Transactions
•Rules-Engine
•Telecom
27

Rails is not enough
Rails is a great
solution...
for the web.
28

Beyond Rails
Apply the Ruby and
Rails philosophies to
enterprise-grade
services.
29

Ruby is just a
syntax
Approach Ruby as just
another syntax for
driving JEE/JVM
technologies.
30

Let’s get
started.
31

Ingredients
JDK6
JBoss AS5
JRuby
Rails
JBoss-Rails
32

JDK6
• OpenJDK is very nice.
•Apple’s JDK6 works just
fine.
33

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/
...
34

Set $JBOSS_HOME
$ cd jboss-5.0.1.GA
$ export JBOSS_HOME=$PWD
$ echo $JBOSS_HOME
/Users/mic/jboss-5.0.1.GA
35

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/
...
36

Prefer JRuby
$ cd jruby-1.2.0RC2/
$ export JRUBY_HOME=$PWD
$ export
PATH=$JRUBY_HOME/bin:$PATH
37

JRuby path
This pulls things like
rake and gem from
JRuby’s path instead of
C-Ruby’s.
38

JBoss-Rails
The Deployer
The first part of JBoss-
Rails is the deployer.
39

JBoss-Rails
The Deployer
The deployer makes
JBoss AS5 Rails-
aware.
40

JBoss-Rails
The Deployer
Install it into the
server’s deployers/
directory
41

Pick a Profile
AS5 provides several
configuration
profiles.
42

The default profile
$JBOSS_HOME/server/default/
43

Drop in the
deployer
44

(or copy it)
$ cp jboss-rails-deployer.jar \\
$JBOSS_HOME/server/default/deployers/
45

Remove ROOT.war
$ rm -Rf $JBOSS_HOME/server/*/deploy/ROOT.war/
46

JBoss-Rails
jboss-rails-support
The second part of
JBoss-Rails is
application-support
library.
47

JBoss-Rails
jboss-rails-support
It goes right into your Rails
app.
So we need a Rails app.
48

Install Rails
$ gem install rails --version 2.2.2
Successfully installed activesupport-2.2.2
Successfully installed activerecord-2.2.2
Successfully installed actionpack-2.2.2
Successfully installed actionmailer-2.2.2
Successfully installed activeresource-2.2.2
Successfully installed rails-2.2.2
6 gems installed
49

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
...
50

Freeze Rails
$ rake rails:freeze:gems
Freezing to the gems for Rails 2.2.2
rm -rf vendor/rails
mkdir -p vendor/rails
cd vendor/rails
Unpacked gem: '/Users/bob/twiggl/vendor/rails/activesupport-2.2.2'
mv activesupport-2.2.2 activesupport
Unpacked gem: '/Users/bob/twiggl/vendor/rails/activerecord-2.2.2'
mv activerecord-2.2.2 activerecord
Unpacked gem: '/Users/bob/twiggl/vendor/rails/actionpack-2.2.2'
mv actionpack-2.2.2 actionpack
Unpacked gem: '/Users/bob/twiggl/vendor/rails/actionmailer-2.2.2'
mv actionmailer-2.2.2 actionmailer
Unpacked gem: '/Users/bob/twiggl/vendor/rails/activeresource-2.2.2'
mv activeresource-2.2.2 activeresource
Unpacked gem: '/Users/bob/twiggl/vendor/rails/rails-2.2.2'
cd -
51

Why freeze?
Relying on system-wide
gems is a bad idea, and
impossible with JBoss-
Rails.
52

JBoss-Rails
jboss-rails-support
Now we can install the
application-support
library.
53

JBoss-Rails
jboss-rails-support
$ cd vendor/plugins/
$ unzip ~/downloads/jboss-rails-support.zip
Archive: /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
.....
54

Apps need
a database.
55

PostgresSQL
56

Create the DB stuff
postgres> create user twiggl
with password 'twiggl';
CREATE ROLE
postgres> create database
twiggl_development
with owner twiggl
encoding 'UTF8';
CREATE DATABASE
57

Set up your app
config/database.yml
development:
adapter: postgresql
database: twiggl_development
username: twiggl
password: twiggl
host: localhost
encoding: UTF8
58

Set up your app
config/database.yml
development:
adapter: postgresql
Just like
database: twiggl_development
username: twiggl
regular Rails!
password: twiggl
host: localhost
encoding: UTF8
59

Database access
Rails on JBoss can take
advantage of JDBC
drivers.
60

Easy JDBC
The jboss-rails-support
library makes it easy to
set up your Rails app for
JDBC.
61

Install the JDBC
gems
$ rake jboss:gems:jdbc:install
62

Install the JDBC
gems activerecord-jdbc
$ rake jboss:gems:jdbc:install
INFO: Installing activerecord-jdbc
adapter-0.8.3
63

Install the JDBC
gems the result
64

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.
65

Deploying a Rails
App
The jboss-rails-
support rake tasks
handle deploying and
undeploying.
66

From your app
$ rake jboss:rails:deploy
Deployed twiggl
67

Deployment Descriptor
$JBOSS_HOME/server/default/deploy/twiggl-
rails.yml
application:
RAILS_ENV: development
RAILS_ROOT: /Users/bob/twiggl
web:
context: /
68

Wait, AS isn’t
running!
69

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: null
13:44:45,283 INFO [ServerImpl] Home Dir: /Users/bob/j boss-5.0.1.GA
13:44:45,283 INFO [ServerImpl] Home URL: file:/Users/bob/jboss-5.0.1.GA/
13:44:45,287 INFO [ServerImpl] Library URL: fi le:/Users/bob/jboss-5.0.1.GA/lib/
13:44:45,288 INFO [ServerImpl] Patch URL: null
13:44:45,288 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: default
13:44:45,289 INFO [ServerImpl] Server Base Dir: /Users/bob/jboss-5.0.1.GA/server
13:44:45,289 INFO [ServerImpl] Server Base URL: file:/Users/bob/jboss-5.0.1.GA/server/
13:44:45,289 INFO [ServerImpl] Server Confi g 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/default
13:44:45,289 INFO [ServerImpl] Server Home URL: file:/Users/bob/jboss-5.0.1.GA/server/default/
70

localhost:8080/index.html
71

Create models
$ jruby ./script/generate resource twig
72

Create models
$ jruby ./script/generate resource twig
...
create app/models/twig.rb
73

Create models
$ jruby ./script/generate resource twig
...
create app/models/twig.rb
...
create db/migrate/20090308180254_create_twigs.rb
74

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
75

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
76

Create models
db/migrate/*_create_twigs.rb
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
end
end
77

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) ======
78

Rough in a controller
app/controllers/twigs_controller.rb
class TwigsController < ApplicationController
def index
@twigs = Twig.find( :all )
end
end
79

Rough in a template
app/views/twigs/index.html.erb
<p>
There are <%= @twigs.size %> twigs.
</p>
<% for twig in @twigs %>
<% div_for( twig ) do %>
<%= twig.name %>
<% end %>
<% end %>
80

Rough in a template
app/views/twigs/index.html.erb
<p>
There are <%= @twigs.size %> twigs.
</p>
<% for twig in @twigs %>
<% div_for( twig ) do %>
<%= twig.name %>
<% end %>
<% end %>
81

Rough in a template
app/views/twigs/index.html.erb
<p>
There are <%= @twigs.size %> twigs.
</p>
<% for twig in @twigs %>
<% div_for( twig ) do %>
<%= twig.name %>
<% end %>
<% end %>
82

Hit it!
83

We didn’t restart
AS.
And we didn’t redeploy
our app, either. That’s
okay, we’re hacking hot
code.
84

Twig management
app/controllers/twigs_controller.rb
class TwigsController < ApplicationController
def new
@twig = Twig.new
end
def create
@twig = Twig.create( params[:twig] )
redirect_to @twig
end
end
85

Twig form
app/views/twigs/new.html.erb
<% form_for @twig do %>
<%= label :twig, :name %>
<%= text_field :twig, :name %>
<%= submit_tag 'Create twig!' %>
<% end %>
86

Twig management
app/controllers/twigs_controller.rb
class TwigsController < ApplicationController
def show
@twig = Twig.find_by_id( params[:id] )
redirect_to twigs_url unless @twig
end
end
87

Twig view
app/views/twigs/show.html.erb
<% div_for @twig do %>
<h1><%= @twig.name %></h1>
<% end %>
88

Create a twig
89

Create a twig
90

Back to the index
91

It’s just like
regular Rails.
92

Beyond Rails
But, we have the entire
freakin’ JBoss AS5
there.
Let’s use it.
93

Job scheduling
Sometimes you need
some code to fire on a
recurring basis, outside of
the web context.
94

Job Scheduling
•Nightly batches
•Polling RSS
•Checking email
•Watching directories
95

Jobs
app/jobs/**/*.rb
96

Job class
app/jobs/twitter_sender.rb
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
97

Job schedule
config/jobs.yml
twitter.sender:
description: Send a tweet
cron: 0 */30 * * * ?
job: TwitterSender
98

Job schedule
config/jobs.yml
twitter.sender:
description: Send a tweet
cron: 0 */30 * * * ?
job: TwitterSender
99

Job schedule
config/jobs.yml
twitter.sender:
description: Send a tweet
cron: 0 */30 * * * ?
job: TwitterSender
100

Job schedule
config/jobs.yml
twitter.sender:
description: Send a tweet
cron: 0 */30 * * * ?
job: TwitterSender
101

Job schedule
config/jobs.yml
twitter.sender:
description: Send a tweet
cron: 0 */30 * * * ?
job: TwitterSender
102

Redeploy the app
$ rake jboss:rails:deploy
103

Why redeploy?
Jobs are deployed when
your app is deployed.
Adding a job means you
need to redeploy your
app.
104

Ta-da!
[RubyJob] Starting Ruby job:
twiggl.twitter.sender
...
[STDOUT] twittering [1 new twigs!]
105

Hot, hot code
Once your job is
deployed, you can
continue to edit the
actual service method.
106

No further
redeployment is
necessary, unless you
add jobs or alter the
schedule.
107

Some More Possibilities
Message Queues (MQ/JMS)
Legacy/JCA integration
WS style web services...
108

Ruby Databinding
JBoss-Rails provides
automatic databinding
to XMLSchema types.
109

Ruby Databinding
When WS deployed, the
WSDL is examined and
real Ruby classes are
created.
110

Shifting gears...
111

What are rules?
Business rules
Declarative statements
Logic/reasoning
112

What are rules?
Capture domain expert
knowledge as
statements/assertions of truth
(aka: business rules)
113

What are rules?
An executable knowledge base
114

Drools
Drools provides a runtime,
compiler and tools to develop
and manage executable
knowledge bases
(all open source of course)
115

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
116

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
117

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
118

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
119

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
120

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
121

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
122

Why?
You have domain experts
The rules change
Anti-spaghetti
if else if else if else ...
123

124

125

126

127

The Guvnor..
Repository and Web interface
128

129

130

131

132

133

134

How?
In process on the JVM
As a decision service
135

Where?
Logistics (Fedex – talk at J1)
Insurance, risk, fraud etc..
All domains..
136

Questions!
For more info:
Contact me: http://twitter.com/michaelneale
http://oddthesis.org/theses/jboss-rails/projects/jboss-rails
http://jboss.org/drools
137