Developing a Business Logic Tier with EJBs

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This tutorial steps you through the development of a business logic tier for a Human Resources application.

Objectives

By the end of this tutorial, you will have learned how to develop a business logic tier using Enterprise JavaBeans. This includes:

• How to create a stateless session bean with the UML modeler
• How to add a field
• How to create a CMP entity bean from a table
• How to create a local reference
• How to add a finder method to an entity bean and call the finder from a method in the session bean
• How to add a create method to an entity bean and how to call it from the session bean
• How to create clients for testing purposes

Requirements

The tutorial will take approximately 90 minutes to complete. You will need the following:

• Oracle9i JDeveloper (9.0.4)
• The tables in the Human Resources (HR) schema. If you are working with a previous version or have dropped those tables, see Creating and Populating the Sample Schema Tables.

Tutorial Scenario

You have been given the task of creating a Human Resources application that can be deployed to multiple platforms, and can use any type of client. To accomplish this task you'll create a business logic tier using Enterprise JavaBeans. The business logic tier will consist of solely Departments, for simplicity. Instead of accessing the entity bean directly from the client, you'll implement the Session Facade design pattern; a session bean will be used to access the entity beans through a local interface.

Application Development

In this tutorial, the development process follows these high-level steps:

1. Create a stateless session bean
2. Create a CMP entity bean from the HR schema tables
3. Create a session bean facade
4. Add a finder method
5. Add a create method

Before you start the tutorial, you'll want to get a brief preview of the tools you'll be using to develop your application in Using the JDeveloper EJB Tools.