Transcript Entity Java Beans - DocJava HomePage

Entity Java Beans
Jorg Janke
http://www.compiere.org
Open Source ERP & CRM
Objectives
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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
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Session Beans
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Entity Bean
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Stateless
Stateful
Bean Managed Persistency
Container Managed Persistency (CMP)
Message Bean
Stateless Session Bean
Stateful Session Bean
Entity Bean
Message Bean
EJB Source Code
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Home Interface (extends EJBHome)
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Remote Interface (EJBObject)
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Create - Find (for Entity)
Factory Pattern
“Business Methods”
Proxy Pattern
Bean Class (EntityBean/SessionBean)
Deployment descriptor (ejb-jar.xml)
EJB Runtime
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Home (“create”, “find”)
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EJB (“business methods”)
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Home Object Stub
Home Object
EJB Object Stub
EJB Object
Bean (“the entity”)
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Enterprise Bean Object
EJB Container - Client
JNDI
Home Stub
Client
Home Stub
Home
Object
RMI-IIOP
Object Stub
Object Stub
Container
EJB
Object
Enterprise
Bean
Object
EJB Use
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Context ctx = new InitialContext();
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BeanHome home = ctx.lookup(“myBean");
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Container finds/creates Factory
BeanRemote bean = home.create();
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JNDI to LDAP or other Directory Service
Container creates EJB Object -> myBean
Bean.doSomething();
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Business Method “Proxy”
Getting started
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The hard way
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Download, Install & Implement the
J2EE Reference Implementation
(Cloudscape)
The easy way
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Select a IDE
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J2EE support often in “Enterprise Edition”
Free: Forte / NetBeans
Now you have your IDE …
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Check what Containers are supported
(or included)
Download & Install the Container
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E.g. JBoss includes Tomcat
IDEs provide
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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”
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Application Server
Business Objects
Coarse Grained Objects
Fine Grained Objects (not suited)
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Local Interface
What is J2EE compliant
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Server providing
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Web Services
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EJB with CMP
JMS, JTA, JAAS
Compliance Test
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Application using
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Servlet, JSP
JNDI, RMI, JDBC
EJB Services
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Version 1.2, 1.3, …
License
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One of the
technologies
Servlet or RMI &
JDBC will do
When to use EJBs
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You need a EJB project for your CV
Highly shared, long lived objects
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Container Managed Persistency (CMP)
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Entity Beans
Data Access Object
Receiving Messages (JMS)
(Simple) Transaction Support (outside JDBC)
Security Support
Compiere & J2EE
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Compiere does not use EJBs
EJB Container (candidate: JBoss)
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Additional Installation effort
Additional Operation effort
Plus: Could be installed automatically
Compiere’s Business Objects (Invoice,..)
dynamically are generated
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Based on Data Dictionary
Business Objects & Behavior are “personalized”
Intro Resources
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http://java.sun.com/j2ee/
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Deployathon
http://java.sun.com/blueprints
http://java.sun.com/j2ee/tutorial
J2EE “community” sites
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http://www.theserverside.com
http://www.middleware-company.com/
http://www.onjava.com (O’Reilly)
Thanks
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You can download the presentation
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http://www.compiere.org/download
My contact:
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http://www.compiere.com/consulting.html
[email protected]