A Java component for EJB Server can be an interface, a class, or a JavaBeans component. You can implement any of these in PowerJ.
An EJB Server Java component follows the Enterprise JavaBeans implementation model. Enterprise JavaBeans (EJB) components are portable to any server that follows Sun’s EJB 1.1 specification. An EJB session Bean models the interaction between an end user and the EJB Server. For example, in an online purchasing application, a session Bean might keep track of a user’s uncommitted purchases. An EJB entity Bean represents a row of data stored in a database. For example, an entity Bean might represent a customer’s purchase order. From the client’s view, entity Beans persist as long as the associated database row has not been deleted. EJB components use standard javax.ejb APIs for component lifecycle and transaction control.
The Enterprise JavaBeans model allow you to use the EJB Server connection caching, transaction management, and lifecycle control features.
There are some restrictions to keep in mind for components. They include:
Parameters for methods in an EJB Server component must have datatypes that can be defined with CORBA IDL.
Classes and JavaBeans components must have a default constructor (a constructor with zero parameters). When you deploy the component to the EJB Server , PowerJ warns you about classes and methods that don’t conform.
