Building J2EE Applications Based on Design Patterns with Business Components for Java

Building J2EE Applications Based on Design Patterns with Business Components for Java Olivier LE DIOURIS Principal Product Manager Oracle Corporation

Agenda • J2EE Overview & Challenges • Design Patterns & Frameworks • BC4J Overview • Demo • Summary

What is J2EE? • Java 2 Enterprise Edition • “The J2EE application model defines an architecture for implementing services as multi-tier applications delivering scalability, portability, and manageability.”

J2EE Architecture - 4 layers Client Tier Web Tier Business Tier Data Tier Clients Presentation Logic Business Logic Data Sources Middle Tier

J2EE Components

What do you need to know to develop J2EE applications? • All tiers:Java • Client tier:Swing • Web tier:JSP, Servlets • Business logic tier:EJB • Connectivity:IIOP • Database access:JDBC • Plus:XML, JNDI, JMS, JTA • The list continues to grow!!

Where do I start ? Application design complexity How do I represent business entities in the middle-tier? How do I enforce business logic? How do I bind and interface client code? How do I keep efficiency More Challenges

Design Patterns • A design pattern describes a proven solution to a recurring design problem • Reasons to use Design Patterns: • They are proven • They are reusable Source: http://java.sun.com/j2ee/blueprints/design_patterns/index.html

Why Framework? “Large scale development of object-oriented software requires frameworks. It is important to have a framework, so that every time the design requires two objects to interact, a developer does not have to come up with a whole new notion of how the interaction works out.” Section 10.2.2.2, Page 253

Benefits of Framework • Better code • Simpler code • Better performing • Less complex

Business Component for Java (BC4J) • BC4J – A J2EE Framework that simplifies Development, Customization and Deployment of J2EE Applications • Implements SUN’s Design Patterns • Standard – Java and XML • Server Side Framework with Client Binding • Based on Oracle’s Developers experience

Major Benefits of BC4J • Simplifying Server Coding • Simplifying Client Binding • Simplifies O/R Mapping • Improve Network using Caching • Hides Complex Infrastructure

Simplifies and optimizes O/R mapping Simplifies and optimizes binding of GUI to logic Flexible Deployment J2EE Framework – BC4J

Map Database Tables to Java Objects Customer CUSTOMER ORDER Order ITEM LineItem Entity Objects

Add Business Rules Customer Status in ‘Platinum’, ‘Silver’, ‘Gold’ CUSTOMER ORDER Order ITEM Valid tracking no. LineItem Buy 10 get 1 free Entity Objects

Customer Status in ‘Platinum’, ‘Silver’, ‘Gold’ OrdView SELECT id,contact, trackno FROM Order ItemView LineItem SELECT id, quantity,discount FROM Item Buy 10 get 1 free Bind Presentation Logic CustView SELECT id, name, statusFROM Customer Order Valid tracking no. View Objects Entity Objects

Customer Status in ‘Platinum’, ‘Silver’, ‘Gold’ PriorityOrder SELECT Order.id, Ord.contact, Ord.trackno, Cust.id, Cust.Status, FROM Order Ord, Customer Cust Order Valid tracking no. Bind Presentation Logic (custom view) View Objects Entity Objects

Middle Tier Caching • Pulls data from database into middle tier and preserves relationships between data • Cache synchronizes data from different view objects that reference that same entity object. • Reduces round trips to database • Control synchronization and locking modes

CustView OrdView Group Components in a Logical Container CustView Customer OrdView Order OrdView ItemView ItemView LineItem Logical Data Model View Objects Entity Objects Application Module

Customer SlowPayingCustomers Bill LatePayments Payment BC4J Clients BC4J RMI/IIOP HTTP Database XML

Building UI for BC4J • HTML UI – JSP • JSP Tag library for BC4J • Java UI – JClient • Swing components with BC4J connectivity • XML UI – JSP • XML messaging from/to BC4J • XSQL Servlet interface to BC4J

Flexible Deployment and Clients HTTP XML JDBC JSP page or servlet Servlet or JSP page on a Java-enabled Web server Browserclient EJB RMI/IIOP JDBC Java GUI client EJB on an application server

Best Practice Steps Our Apps Teams Follow • Design Application Business Model • Using UML Class Diagrams • Implement Application Business Model • Using of BC4J Framework • Identify Application Task • Using UML Use Cases • Implement Application Data Model for the Task • Using BC4J Framework • Bind Interfaces to Application Data Model • Swing, JSP, or XML • Test Interface and Select Deployment Target • Decide to Target Web Tier or EJB Tier

BC4J D E M O N S T R A T I O N

BC4J = Easier J2EE • J2EE Can be complex • BC4J Makes J2EE Simple • BC4J Is standard based Java+XML • BC4J is part of JDeveloper

Where to get more Information http://otn.oracle.comhttp://technet.oracle.com • Complete technical resource for developers • Software, samples,& code downloads • Discussion forums • Whitepapers, technical information, documentation http://www.oracle.com Product news, Press Release, customer stories

Building J2EE Applications Based on Design Patterns with Business Components for Java