Enterprise JavaBeans, Fourth Edition

The Customer EJB

The Customer EJB is a simple CMP entity bean that models the concept of a cruise customer or passenger, but its design and use are applicable across many commercial domains. This section introduces the Customer bean’s development, packaging, and deployment. We greatly expand the bean’s features as we progress through the chapter.

The Customer Table

Although CMP is database-independent, the examples throughout this book assume that you are using a relational database. This means that we will need a CUSTOMER table from which to get our customer data. The relational database table definition in SQL is as follows:

CREATE TABLE CUSTOMER 
(
    ID INT PRIMARY KEY NOT NULL, 
    LAST_NAME CHAR(20), 
    FIRST_NAME CHAR(20)
)

The CustomerBean

The CustomerBean class is an abstract class that the container uses for generating a concrete implementation, the persistence entity class. The mechanism used by the container for generating a persistence entity class varies, but most vendors generate a subclass of the abstract class provided by the bean developer (see Figure 6-4).

Figure 6-4. The container tool typically extends the bean class

The bean class must declare accessor (set and get) methods for each persistence field and relationship field defined in the deployment descriptor. The container needs both the abstract accessor methods (defined in the entity bean class) and the XML elements of the ...