Using Ejbs - MACROMEDIA 38000382 - JRun - Mac Getting Started Manual

Using EJBs

EJBs provide a component architecture for building distributed object-oriented business
applications using Java. An application server that supports EJBs allows Java developers
to concentrate on implementing the business logic of an enterprise application as
reusable components. The EJB server handles the complexity of lower-level services, such
as component life cycle, state management, persistence, multithreading, connection
pooling, transaction management, and security.
The EJB specification defines the following types of Enterprise JavaBeans:
The following constructs are available to access an EJB:
Construct
remote home
interface
local home
interface
(new in EJB 2.0)
remote interface
local interface
(new in EJB 2.0)
EJB
implementation
class
90 Lesson 3 EJB Tutorial
Represent a business process.
Session beans
Represent an object view of data from any source, typically a row in a
Entity beans
relational database.
Message-driven beans
(JMS) listener.
Extends
EJBHome
EJBLocalHome
EJBObject
EJBLocalObject
Combine features of an EJB and a Java Message Service
Description
Defines the EJBs life-cycle methods that can be
accessed from applications outside the EJB
container: methods to create (obtain), find, or
remove an EJB instance.
Defines methods to create (obtain), find, or
remove an EJB instance on behalf of the client,
that are located in the same EJB container.
Defines the EJBs business methods that can be
accessed from applications outside the EJB
container: the business methods an EJB presents
to the outside world to do its work.
Defines the EJBs business methods that can be
used by other EJBs located in the same EJB
container. The local interfaces allow EJBs to
interact without the overhead of a distributed
object protocol.
Provides the implementation of the business and
life-cycle methods. It must have methods
matching the signatures in the remote and local
interfaces and methods corresponding to some of
the methods in both the remote and local home
interfaces.