Introduction to seam_applications_formated
- 1. Introduction to Seam Applications Nuwan Gunarathna www.geveo.com
- 2. Agenda Common WebApp Development Patterns.
- 3. Why Seam?
- 4. Features.
- 5. CRUD App demo with seam-gen.
- 6. Q&A
- 7. Today’s Web Applications Too many layers Too many Integration Points
- 8. Too much Xml configuration For new features, You have to lean new Frameworks
- 10. JSF falls short – Not fully enough for Web 2.0
- 11. Not a platform, merely a set of libraries and wrappers
- 12. Documentation is not at one place(Too many dependent frameworks)
- 13. Why Seam? To provide a Complete solution for Java Web Application Whithin an Application Is it good? Yes. Gavin King
- 14. Some Good Reasons Stateful Wep Applications All components are inherently stateful – no need state management Code Configuration by Exception( convention over configuration ) Idea is to have a common-sense default behaviors for components Gluing JSF and EJB3 across framework boundaries. Collapse artificial façade object layer in between Annotation based integration
- 15. Gives correct wayt to use ORM Lazy loading just works fine: Eliminate most encountered Exception with stateless frameworks all the time
- 16. Only framework that support lazy loading correctly in web application
- 17. Some Good Reasons cont.. No more DTOs to write
- 18. POJO as business services No framework interfaces, No Abstract classes
- 19. Using dependency bijection App Generator via seam-gen (aka scaffolding)
- 20. It makes persistence a breeze
- 21. Annotations over XML, end to end
- 22. Automated integration testing using TestNg and JUnit
- 23. And many more … (Rules Engine, BPM, Ajax Support, Pdf, E-mail, RESTful …)
- 24. Open source. Open standards. Future of Java EE
- 25. Layers in Seam View (JSF/Wicket/GWT/Flex etc.,) Business Layer (SFSB/SLSB/POJO) DB Persistence Layer (Entities) Hey, No Integration Layer! Seam exposes Business Layer objects and their attributes on the front-end using EL expressions. No DAOs
- 26. No DTOs
- 27. Contextual Components Most of the problems relate to state management
- 28. Traditional contexts for Java Servlets focused on technology instead of on application
- 29. EJB itself has no strong model of state management
- 30. We need a richer context model that includes “logical” context
- 31. We should be able to use annotations everywhere
- 32. An EJB should be able to be a JSF managed bean (vice versa)
- 33. Main idea: realization of desktop-like wizards and dialogs, possibly in parallel
- 34. It makes sense to think of binding EJB components directly to the JSF view
- 35. The Seam Context Model *source: www.reverttoconsole.com
- 36. Conversations Conversations are not that exciting until you really start thinking about them:
- 39. Stack of continuable states (nested conversation)
- 40. No more HttpSession object Reduce codes and memory leaks Avoid unexpected behaviors with multiple browser windows
- 41. Conversations Cont.. Allows multiple concurrent state containers for a single user over HTTP session
- 42. Each conversation resides in its own Browser or Tab User Session Browser1 Browser2 Browser3 User Concurrent Conversations C3 C2 C1
- 43. Page Flow/Navigation Rules Seam specific file to enhance page navigation pages.xml integrates stateful components Manage complicated navigation flows based on current state of the application
- 44. Define navigation rules for each page
- 45. Flow is based on events and conditions
- 46. New Programing Patterns EntityHome Manage persistence state of a single Object
- 47. CRUD operations
- 48. • persist();
- 49. • getInstance();
- 50. • update();
- 51. • remove(); EntityQuery Manage JP/EJB QL(Query Language) result se t
- 52. Ajax Support Seam's totally unique concurrency model and state-management model was conceived and designed with AJAX in mind.
- 53. Page Wide Support (region, zone) Add support to existing components
- 55. Partial tree rendering, partial page refresh Component Wide Ajaxified components
- 57. Integration Testing Seam components can easily be tested in TestNG or Junit
- 58. The JBoss Embeddable EJB3 container is a great platform for integration testing: perform an end to end testing in it’s own embeddable container -- in a single unit test!
- 59. Test he entire flow of a request or conversation
- 60. Test all layers of Java code in the application, from presentation to persistence.
- 61. Seam-gen Generate a project structure with build
- 63. Reverse engineering of POJOs
- 64. Entity model validations enforced with ajax feedback
- 65. Generates Ant build script itself
- 66. Ready made project files for eclipse, netbeans, idea
- 67. Basic page level authorization
- 68. Datasource creation and configuring persistence layer
- 70. Other Technologies? But what about Spring, Spring MVC, Grails, hibernate stack or JSF?
- 71. Grails ... Probably. Leverage the Groovy programming language But Seam is: An “application stack” not a “web framework”
- 72. A unified development platform of {programming model, frameworks, best practices and tooling}
- 73. Resources Reference docs, more than 30 examples, forums and best overall place - www.seamframework.org
- 74. Richfaces 3.3 - http://www.jboss.org/jbossrichfaces/docs/
- 75. Richfaces book – Practical Richfaces (Max Katz)
- 76. JSF 2 (includes “seam” like features) - http://nejug.org/events/show/91
- 77. EJB 3.1 - http://jcp.org/en/jsr/detail?id=318
- 78. Seam Books – Seam in Action (Dan Allen) & Seam Framework – Experience the evolution of Java EE (Jacob Orshalick)
- 79. Tools: JBoss Tools for Eclipse. Intellij and Netbeans also have excellent support for Seam