Smokejumping GrailsRobert Fischer, Smokejumper Consultingrobert . fischer @ SmokejumperIT . com

Presented Nov 17th, 2008at the Triangle Java User Group (TriJUG)

1Tuesday, November 18, 2008

Hi, I’m Robert2Tuesday, November 18, 2008

Math Major3Tuesday, November 18, 2008

Born and Raised in Perl4Tuesday, November 18, 2008

Agile Java Consultant5Tuesday, November 18, 2008

Technical BloggerEnfranchisedMind.com• The Joy of BDD, or, Re-writing Your Code in

Mocks and Asserts is Not Unit Testing

• Functional (Meta)?Programming Stunts for Ruby and Groovy (and a Little Perl)

• 7 Actually Useful Things You Didn’t Know Static Typing Could Do: An Introduction for the Dynamic Language Enthusiast

• A Defense of Prototypes, or, Why Does Tom Christiansen Hate Perl?

6Tuesday, November 18, 2008

Groovy/Grails Fanboy

• Introduced to Groovy/Grails at Carol.com, Active in Groovy Users of Minnesota

• Uses Grails as freelancer to quickly develop prototype applications

• Regular on IRC: FreeNode #groovy, #grails

• Active on Groovy and Grails mailing lists

• Autobase and BackgroundThread plugin

7Tuesday, November 18, 2008

All Web App Development Should

Be Grails

8Tuesday, November 18, 2008

No, Really.

• Stunningly simple development.

• Succinct code using a superset of Java.

• Sane defaults, straightforward configuration.

• Static typing as deemed useful by developer.

• Standard deployment approach.

• SpringSource backed and here to stay.

9Tuesday, November 18, 2008

What Is Grails?

• Web application development framework/environment leveraging Java and Groovy.

• Convention-based MVC development with a set of powerful command-line tools.

• Powered by pre-configured and pre-integrated Spring, Hibernate, SiteMesh, and JUnit.

10Tuesday, November 18, 2008

How Would YouLike Your Grails?

• Conceptually thin dynamic MVC framework

• Dynamic, succinct domain and controllers

• Run from source code check-out

• Mash-up with extensible plugin architecture

• Actually approachable best-of-breed Java stack

• Prepackaged Java environment and build system

• Builds a WAR to plug into existing deployments

• Hooks for existing Spring and Hibernate config

11Tuesday, November 18, 2008

Grails BeforeYour Very Eyes!

Live Coding!

12Tuesday, November 18, 2008

But Wait, There’s More!Plugins

• Functional Testingwebtest, selenium, fitnesse

• Rich User Interface (RIA)grails-ui, richui, gwt, flex, yui, iui

• Database Management: Autobase

• Background Tasks: BackgroundThread

• And dozens more: http://grails.org/plugins

13Tuesday, November 18, 2008

Autobase

• Manages database state using a non-linear collection of database change sets.

• Leverages existing Grails database automation to minimize effort.

• Provides a Liquibase-based embedded DSL for database migrations.

• http://github.com/RobertFischer/autobase/wikis/

14Tuesday, November 18, 2008

Example Migration

changeSet(id:'rename_bar_to_baz', author:'Robert'){ dropColumn(tableName:'foo', columnName:'baz') renameColumn(tableName:"foo", oldColumnName:"bar", newColumnName:"baz")}

15Tuesday, November 18, 2008

Background Thread

• Provides a Spring bean that will execute arbitrary closures in the background.

• Handles some awkwardness around Hibernate sessions, and provides thread pooling and logging.

• http://grails.org/BackgroundThread+Plugin

16Tuesday, November 18, 2008

BackgroundThread Usage Example

class FooService {

boolean transactional = false def backgroundService

def serviceMethod() { (1..<10).each { cnt -> backgroundService.execute("Logging '$cnt'”, { log.info("${cnt}") }) }

}

17Tuesday, November 18, 2008

But What AboutJRuby on Rails?

18Tuesday, November 18, 2008

My JRuby on RailsStreet Cred

• Work history in Rails, including last 5 months on a JRuby on Rails project

• Regular attendee, competition member, and one-time presenter at Ruby Users of Minnesota (RUM)

• Charlie “Headius” Nutter fan

19Tuesday, November 18, 2008

Why NotJRuby on Rails?

• Although Java-in-Ruby is fairly slick, Ruby-in-Java is pretty rough and best mediated via Groovy metaprogramming

• GORM is superior to ActiveRecord

• http://www.oreillynet.com/ruby/blog/2007/05/bind_parameters_now.html

• GSPs are superior to ActionView

• Spring is superior to nothing

• Optional static typing is superior to pure dynamic typing

• You can code Grails without grokking its source

• Nobody is fired for choosing Java

20Tuesday, November 18, 2008

The One Circumstance I Would Still Use Rails• Small CRUD-based app with its own DB

• No or very generous performance limits

• Owned by one or two developers

• Expected life cycle of less than a year

• Deployed system is without Java or is an Apache web server with mod_passenger and without mod_proxy or mod_jk

21Tuesday, November 18, 2008

Your GrailsAdoption Plan

• Best approach: start with a roughly green-field proof-of-concept web application

• Use GRAG on SourceForge to generate a database front-end to impress your boss

• Wrap an existing Java web application in Grails and use web.xml (installed via “grails install-templates”) to map urls to servlets

22Tuesday, November 18, 2008

Resources

• Home Pages:http://grails.orghttp://groovy.codehaus.org/

• Live Open Source ApplicationsGrails CrowdGrails.orgGroovy Blogs

• MediaGroovy & Grails PodcastGroovyMag

23Tuesday, November 18, 2008

Groovy Mag24Tuesday, November 18, 2008

Sold?Want to know more?• Robert is offering “Introduction to Groovy,

Grails, and AJAX” training in the Triangle on December 15th through 18th. Additional training courses will be offered next year.

• Subscribe to “Smokejumper Training” Google Group for more information.

• On-demand training, technical leadership, and mentoring services are also available.http://SmokejumperIT.com

25Tuesday, November 18, 2008