Entity Java Beans Jorg Janke Open Source ERP & CRM

Objectives Know J2EE & EJB Buzzwords Understanding of J2EE Architecture Understanding of EJB Architecture Know next steps to explore J2EE & EJB

Java Application Tiers

Java Application Tiers (Detail)

J2SE

EJB Types Session Beans Stateless Stateful Entity Bean Bean Managed Persistency Container Managed Persistency (CMP) Message Bean

Stateless Session Bean

Stateful Session Bean

Entity Bean

Message Bean

EJB Source Code Home Interface (extends EJBHome) Create - Find (for Entity) Factory Pattern Remote Interface (EJBObject) “Business Methods” Proxy Pattern Bean Class (EntityBean/SessionBean) Deployment descriptor (ejb-jar.xml)

EJB Runtime Home (“create”, “find”) Home Object Stub Home Object EJB (“business methods”) EJB Object Stub EJB Object Bean (“the entity”) Enterprise Bean Object

EJB Container - Client Client Container Home Stub Object Stub RMI-IIOP Home Object EJB Object Enterprise Bean Object JNDI

EJB Use Context ctx = new InitialContext(); JNDI to LDAP or other Directory Service BeanHome home = ctx.lookup(“myBean"); Container finds/creates Factory BeanRemote bean = home.create(); Container creates EJB Object -> myBean Bean.doSomething(); Business Method “Proxy”

Getting started The hard way Download, Install & Implement the J2EE Reference Implementation (Cloudscape) The easy way Select a IDE J2EE support often in “Enterprise Edition” Free: Forte / NetBeans

Now you have your IDE … Check what Containers are supported (or included) Download & Install the Container E.g. JBoss includes Tomcat IDEs provide Wizards / Templates Packaging & Deployment

For a live demo … visit me

JBuilder New …

New Module (multiple Beans)

New Session Bean

Stateless Session Bean

Session Bean Properties

Home Interface

Remote Interface

Bean Class

Deployment Descriptor

Add additional methods …

Create Test Client

Client 1 – Lookup

Client 1 - Create

Client 1 – Business Methods

Entity Bean

Home Interface

Remote Interface

Bean Class

Client 2

Client 2 – Lookup / Create

Client 2 – Business Methods

Java Application Tiers

How do EJBs “fit in” Application Server Business Objects Coarse Grained Objects Fine Grained Objects (not suited) Local Interface

What is J2EE compliant Server providing Web Services Servlet, JSP JNDI, RMI, JDBC EJB Services EJB with CMP JMS, JTA, JAAS Compliance Test Version 1.2, 1.3, … License Application using One of the technologies Servlet or RMI & JDBC will do

When to use EJBs You need a EJB project for your CV Highly shared, long lived objects Entity Beans Container Managed Persistency (CMP) Data Access Object Receiving Messages (JMS) (Simple) Transaction Support (outside JDBC) Security Support

Compiere & J2EE Compiere does not use EJBs EJB Container (candidate: JBoss) Additional Installation effort Additional Operation effort Plus: Could be installed automatically Compiere’s Business Objects (Invoice,..) dynamically are generated Based on Data Dictionary Business Objects & Behavior are “personalized”

Intro Resources Deployathon J2EE “community” sites (O’Reilly)

Thanks You can download the presentation My contact: