Java EE and Google App Engine
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This document summarizes a presentation about using Google App Engine (GAE) and Contexts and Dependency Injection (CDI) on Java EE applications. It discusses initial problems with using GAE and CDI due to limitations of the platforms and differences between development and production environments. It also covers solutions to these problems including abstracting the GAE API, using CDI extensively, and thorough testing. The goal is to build applications that can be ported between GAE and JBoss Application Server.
Java EE and Google App Engine
- 1. Aleš Justin, JBoss by RedHat JavaEE and Google AppEngine Tuesday, April 12, 2011
- 2. Agenda • What is GAE and CDI? • Why GAE and CDI? • Other JavaEE technologies • Development vs. Production • Problems vs. Solutions • Testing •Q & A Tuesday, April 12, 2011
- 3. About me • Old school JBoss-ian • Microcontainer co-author • Weld lead • RHT Cloud “guinea pig” • Eager PaaS user • While still GAE amateur Tuesday, April 12, 2011
- 4. GAE • Forked Jetty • Many (logical) restrictions • RDBMS → BigTable • Simple Map(Reduce) • Good administration • Free basic usage Tuesday, April 12, 2011
- 5. CDI • Context and Dependency Injection • JSR-299 → JBoss Weld RI • “type-safe” programming • “contexts” concept • Easy to extend: “Extensions” • “Using CDI Extensions to Make a Better Java EE ” at 18:00 Tuesday, April 12, 2011
- 6. Why GAE and CDI? • Simple reason: sandbox app • Android app with server back-end • Tattletale (Tožibaba) • Zero administration / configuration • Reliable up-time • No more “boiler-plate” code → CDI Tuesday, April 12, 2011
- 7. CDI #2 • @Inject • @Observes • @Qualifier • @ConversationS. • @Named • @Decorator • @Scope • @Alternative • Interceptors • @Sterotype • InjectionPoint • Instance • Pete and Dan’s • @Produces yday tutorial! Tuesday, April 12, 2011
- 8. Other technologies • JPA • JSF2 • BeanValidation • javax.cache • JSON • ShrinkWrap + Arquillian Tuesday, April 12, 2011
- 9. Project Kick-Off • Know (all) restrictions! • 30sec, white-list, no threads, ... • How portable should my app be? • Development vs. Production Env! • Frameworks have problems • But they mostly have (easy) solutions → fork? Tuesday, April 12, 2011
- 10. The Goal • Abstract away GAE API • Pure JavaEE • Port app to JBossAS (6 & 7) • Use CDI as much as possible • Test it all, same as other JavaEE apps Tuesday, April 12, 2011
- 11. Initial problems Proxy Bean • CDI • “Entry” mechanism • Request / response binding • Lack of “lifecycle” handling Tuesday, April 12, 2011
- 12. Initial problems • JPA • Limited relationships (Entity groups) • Proxying layer vs. Custom “ORM” • Transaction per “Entity group” • Old DataNucleus version • Long vs. Key entity key • “Enhanced” entities • GeoModel hashing queries (“IN”) Tuesday, April 12, 2011
- 13. Initial problems • JSF2 • Context parameter settings • “new InitialContext” patch • “built-in” EL 1.0 → workaround Tuesday, April 12, 2011
- 14. Initial problems • BeanValidation • Static usage with JPA • Size • Configuration Tuesday, April 12, 2011
- 15. Initial problems • javax.cache (GCache) • No partition • NUCCORE-540 → fork • JSON • Different versions; client vs. server • Arquillian • Missing GAE container Tuesday, April 12, 2011
- 16. “Production” problems • CDI • “Bean scanning” → exact listing • “Lazy beans” → MVC re-write • GZIP + Base64 usage • “Fall-back / repeat” mechanism Tuesday, April 12, 2011
- 17. “Production” problems • JPA • Explicit entity listing • Maximize cache usage • “Caching” → Lazy EMF • javax.cache • serialVersionUID • Non-primitive variables • Cache evict / clear mechanism Tuesday, April 12, 2011
- 18. Testing • ShrinkWrap • Binaries abstraction • Arquillian • Runtime / Env abstraction • https://github.com/alesj/arquillian Tuesday, April 12, 2011
- 19. Tattletale • Lhotse POC • https://github.com/alesj/lhotse Lhotse Server-API Tattletale Server-GAE Server-JEE Tuesday, April 12, 2011
- 20. Q&A ales.justin@jboss.org Tuesday, April 12, 2011