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Seminar: Enterprise JavaBeans

Seminar: Enterprise JavaBeans. Agenda Java™ 2 Platform Java™ 2 Platform,Enterprise Edition(J2EE) Enterprise JavaBeans ™ Enterprise JavaBeans ™ Architecture. Java™ 2 Platform. Java History. 1995 Sun World95 1996 JDK1.0 Final Release 1997 JDK1.1 Final Release

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Seminar: Enterprise JavaBeans

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  1. Seminar: Enterprise JavaBeans

  2. Agenda • Java™ 2 Platform • Java™ 2 Platform,Enterprise Edition(J2EE) • Enterprise JavaBeans ™ • Enterprise JavaBeans ™ Architecture

  3. Java™ 2 Platform

  4. Java History • 1995 Sun World95 • 1996 JDK1.0 Final Release • 1997 JDK1.1 Final Release • 1999 JDK1.2 Final Release • 2000 JDK1.3 Final Release

  5. Today/Tomorrow Web Content E-mail Entertainment Travel Personal Finance E-commerce Voice Over IP Long Distance Phone

  6. Today’s Enterprise

  7. Short History of Java Enterprise Technology

  8. Java™ 2 Platform • Java™ 2 Platform,Standard Edition(J2SE) • Java™ 2 Platform,Enterprise Edition(J2EE) • Java™ 2 Platform,Micro Edition(J2ME)

  9. Java™ 2 Platform

  10. Java History

  11. Java Enterprise Architecture Workstation PC Web Server Video Server BeeperCell PhoneATM Game PDA Corporate LAN Solstice Firewall Public Internet CorporateIntranet Workgroup Server Firewall Kiosk Mainframe Server Java Desktop Java Device

  12. Agenda • Java™ 2 Platform • Java™ 2 Platform,Enterprise Edition(J2EE) • Enterprise JavaBeans ™ • Enterprise JavaBeans ™ Architecture

  13. Java™ 2 Platform Enterprise Edition(J2EE)

  14. Application Servers • Provides infrastructure to support management of business logic and access to services • Provide proprietary APIs,which leads to vendor lock • Diminishes ability to reuse business logic on another vendor’s application servers

  15. Enterprise Goals • Reuse • Interoperability • Portability • Time-to-Market

  16. Concurrency Scalability Availability Security EIS Integration Distribution Consistency Administration Why another Java 2 Platform? Enterprise Services Require

  17. What is J2EE ? • J2EE is An Integrated Application Environment ( consist of below ) • API specifications (EJB,JSP,JDBC etc)Defines J2EE requirements • Reference implementation of APIsOperational J2EE platform • Compatibility tests with brandingValidates J2EE platform compatibility • Application Programming ModelDescribes how to build J2EE application

  18. What is J2EE ? • The enterprise developer can concentrate on application components,not the underlying services • Separation of business logic and services provide for better reuse of business logic Business logic Business logic Services Services

  19. J2EE Architecture

  20. J2EE API Summary • J2SE 1.3 • JDBC 2.0 • RMI/IIOP 1.0 • EJB 1.1.x • Servlet 2.2 • JSP 1.1 • JNDI 1.2 • JTA 1.0 • JMS 1.0 • JavaMail 1.1 • JAF 1.0

  21. J2EE Standard Services Services Java Technology • Web • Database • Naming and Directory • Management • Email • Protocol • Transaction Servlet/JSP(HTML/XML) JDBCTM JNDI JMX JavaMail TM JavaIDL/RMI OTS/JTS/JTA

  22. J2EE Platform

  23. J2EE is important • Integrated Application Environment • Open platform • Integrates with existing environments • Provides foundation for future development

  24. Agenda • Java™ 2 Platform • Java™ 2 Platform,Enterprise Edition(J2EE) • Enterprise JavaBeans ™ • Enterprise JavaBeans ™ Architecture

  25. Enterprise JavaBeans ™

  26. EJB Architecture

  27. EJB Design Goals • Simplify development/deployment of distributed applications • Achieve broad industry acceptance • The right expert focuses on the right job • Platform independent and protocol neutral • Enable development of portable components - Truly enable reuse

  28. Defining Enterprise JavaBeans • A server-side component architecture • Model to enable efficient development and deployment of Java applications : • Transactional,Portable • Distributed,Multi-tier • Scalable • Secure

  29. Defining Enterprise JavaBeans • EJB is not JavaBeans • a Server Component specification for Java • Separates business and system programming • Portability of business objects • Extensibility through vendor features

  30. JavaBeans Versus Enterprise JavaBeans Java Beans • Can be either visible or non-visible • Intended to be local to a single process on the client side • Uses the BeanInfo classes, Property Editors & Customizers to describe itself • Can also be deployed as an ActiveX control Enterprise JavaBeans • Are decidedly Non-Visible, remote objects • Remotely executable components deployed on the server • Uses the Deployment Descriptor to describe itself • Can not deployed as an ActiveX control since OCXs run on the desktop

  31. JavaBeans Versus Enterprise JavaBeans Server Enterprise information Services Client Java Beans Container Java Beans EJB1 Database Java Beans Existing application EJB2 Client Java Beans EJB3 Server manages resources such as threads, connection pooling, caching, and state management Java Beans

  32. What Is Special About EJBs? • Learn once • Write Once, Run Anywhere TM • Portable and interoperable • Flexible and extensible • Scalable • Easier to write distributed applications • Transaction management • CORBA compatible

  33. Agenda • Java™ 2 Platform • Java™ 2 Platform,Enterprise Edition(J2EE) • Enterprise JavaBeans ™ • Enterprise JavaBeans ™ Architecture

  34. Enterprise JavaBeans ™ Architecture

  35. Key Components in EJB • EJB Server • EJB container • Home Object • EJBObject • Enterprise Bean

  36. EJB Architecture Overview EJB Home Interface EJB Home Class EJB Object Interface EJB Object Class EJB Class EJB Container Deployment Descriptor Manifest EJB Server

  37. Home Object 5 4 Client EJB 6 7 EJB Object 9 10 1 3 11 8 Enterprise Properties Services JNDI 2 Naming Transaction Persistence Security EJB Architecture Overview

  38. Application Life Cycle

  39. EJB Server • Provides System Services • Transaction support • Database access • System resource • Namespace • Implementations • Middleware servers • Application servers • Database servers

  40. EJB Server • Supplies containers for EJBs • API between server and container is currently vendor specific • Server could provide several container types to provide various extended services to different beans

  41. EJB Container • Currently provided by EJB Server • EJB access to server resource through standard API • May Contain one or multiple classes • Tools for EJB creation and deployment

  42. EJB Container • Some standard services • Persistence • EJB instance creation & location • Namespace • Transaction control • Swapping • Security • Custom services • Application-specific • Bridge to existing systems

  43. Home Interface • Factory interface for the bean: • Interface provided by EJB developer • Class generated by vendor tool • One factory class per bean class • Factory instance is installed into the server’s naming service

  44. Home Interface import java.io.Serializable; import java.rmi.RemoteException; import javax.ejb.CreateException; import javax.ejb.EJBHome; public interface ConverterHome extends EJBHome { Converter create() throws RemoteException, CreateException; }

  45. Remote Interface • Interface is provided by bean developer • Implementation is provided by container tools, which include • Stubs and Skeletons • The EJB Object

  46. Remote Interface import javax.ejb.EJBObject; import java.rmi.RemoteException; public interface Converter extends EJBObject { public double dollarToYen(double dollars) throws RemoteException; public double yenToEuro(double yen) throws RemoteException; }

  47. EJB Object • The EJB Object is a wrapper object that Acts as a proxy to the EJB instance • Interface provided by Bean Developer • Implementation class generated by tool • Each business method has a corresponding method in the EJB Object • Wrapper method implements container- provided services

  48. EJB Architecture Overview Home Object Home Interface Client EJB Object Bean Skeleton Remote Interface EJB Stub Remote Interface EJB

  49. EJB Source import java.rmi.RemoteException; import javax.ejb.*; public class ConverterEJB implements SessionBean { public double dollarToYen(double dollars) { return dollars * 121.6000; } public double yenToEuro(double yen) { return yen * 0.0077; } public ConverterEJB() {} public void ejbCreate() {} public void ejbRemove() {} public void ejbActivate() {} public void ejbPassivate() {} public void setSessionContext(SessionContext sc) {} }

  50. Types of EJBs Session Beans Client state Server Container Enterprise information Services Client Proxy EJB1 Database Proxy EJB2 Existing application Client Proxy EJB3 Entity Beans State of data

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