La presentazione di Aleš Justin, in occasione del Codemotion, Roma 5 marzo 2011 http://www.codemotion.it

1. JavaEE and
Google AppEngine
Aleš Justin, JBoss by RedHat
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

2. Agenda
• What is GAE and CDI?
• Why GAE in CDI?
• Other technologies
• Problems and solutions
• Testing
• Q&A
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

3. About me
• Old school JBoss-ian
• Microcontainer co-author
• Weld lead
• Amateur GAE user
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

4. GAE
• Forked Jetty
• Many (logical) restrictions
• RDBMS → BigTable
• Simple Map(Reduce)
• Good administration
• Free basic usage
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

5. CDI
• Context and Dependency Injection
• JSR-299 → JBoss Weld RI
• “type-safe” programming
• “contexts” concept
• Easy to extend: “Extensions”
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

6. Why GAE + CDI?
• Simple reason: playing with CDI and GAE
• Android app with server backend → Tattletale
• Zero administration / configuration
• Reliable up-time
• No more “boiler-plate” code → CDI
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

7. CDI #2
• @Inject
• @Produces
• @Qualifier
• @Observes
• @Named
• @ConversationScoped
• @Scope
• @Decorator
• Interceptors
• @Alternative
• InjectionPoint /
• @Stereotype
Instance
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

8. Other technologies
• JPA
• JSF2
• BeanValidation
• javax.cache
• JSON
• ShrinkWrap + Arquillian
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

9. Initial problems
• CDI
• “Entry” mechanism
• Request / Response binding
• Lack of “lifecycle” handling
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

10. Initial problems
• JPA
• Limited relationships (Entity Groups)
• Transaction per “Entity Group”
• Old DataNucleus version
• Long vs. Key entity key
• “Enhanced” entities
• GeoModel hashing queries (“IN” keyword)
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

11. Initial problems
• JSF2
• Context parameter settings
• “new InitialContext” → patch
• “built-in” EL 1.0 → workaround
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

12. Initial problems
• BeanValidation
• Static usage with JPA
• Size
• Configuration
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

13. Initial problems
• javax.cache (GCache)
• No partition
• NUCCORE-540 → hack
• JSON
• Different versions → patch → bug
• Arquillian
• Missing GAE “container” implementation
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

14. “Production” problems
• CDI
• “Bean scanning” → patch
• “Lazy bean creation” → MVC re-write
• GZIP + Base64 usage
• “Fall-back / repeat” mechanism
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

15. “Production” problems
• JPA
• Explicit entity usage
• Maximize cache usage
• “Caching” → Lazy EMF
• javax.cache
• serialVersionUID!
• Non-primitive variables
• Cache evict/clear mehanizem
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

16. Testing
• ShrinkWrap
• Arquillian
• https://github.com/alesj/arquillian
• DEMO
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

17. Tattletale PR
http://tehnik.mobitel.si/m-android-
glasovanje/?app=8
Android 1.5+
➠ GAE
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011

18. Q&A
• Tattletale ➠ Weld
• Tattletale ➠ JBossAS
Aleš Justin - ales.justin@jboss.org
Saturday, March 5, 2011