Copyright © 2002 ProsoftTraining. All rights reserved. Enterprise JavaBeans

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 1: Introduction to Server-Side Component Software

Objectives Define client-server and multi-tier architecture Discuss the benefits and issues of distributed architectures Define software components Discuss server-side component architecture and architecture solutions Define J2EE technologies Define EJB technology

Client-Server and Multi-Tiered Architectures Scalability Extensibility Security Issues concerning distributed architectures –Complexity –Communication/bandwidth –Maintenance costs

Centralized Mainframe Architecture

Two-Tier Architecture

Three-Tier Architecture

Software Components Component architectures –Component development tools –Container –Maintenance deployment tools

Component Architecture Solutions.NET Enterprise Architecture CORBA J2EE

J2EE Technologies EJB RMI/RMI-IIOP JNDI JDBC JTA/JTS JMS JSP IDL JavaMail Connectors XML

Enterprise JavaBeans Differences between JavaBeans and Enterprise JavaBeans EJB development tasks –J2EE product provider –Bean developer –Application assembler –Deployer –System administrator –Tool provider

Summary Define client-server and multi-tier architecture Discuss the benefits and issues of distributed architectures Define software components Discuss server-side component architecture and architecture solutions Define J2EE technologies Define EJB technology

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 2: Overview of the Enterprise JavaBeans Framework

Objectives Define an EJB server’s main components Discuss EJB and client interaction Identify EJB container services Describe home objects and EJB objects Compare session beans and entity beans Define a deployment descriptor Identify the EJB-JAR file

EJB Architecture Primary components –EJB-compliant server –EJB-compliant container –Home object (bean factory) –EJB object (remote interface) –EJB

Example of EJB Architecture

Client Interaction with Enterprise JavaBeans

EJB Container Services Distributed transaction management Persistence Security Component resource and life cycle management Remote accessibility Transparent location of components Identification of components

The EJB Home Object Location transparency

The EJB Object Stubs Skeletons

Types of Enterprise JavaBeans Session beans –Stateful –Stateless Entity beans

Deployment Descriptors An XML document that describes the properties of an EJB

The EJB-JAR File Contains the class files for a bean, its home and remote interfaces, and the deployment descriptors

Summary Define an EJB server’s main components Discuss EJB and client interaction Identify EJB container services Describe home objects and EJB objects Compare session beans and entity beans Define a deployment descriptor Identify the EJB-JAR file

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 3: Creating Session Beans

Objectives Define the methods of the SessionBean interface Describe the EJBContext and the SessionContext interfaces Contrast stateful and stateless session beans Explain how to write business methods for a session bean Discuss the enterprise bean’s life cycle

Objectives (cont’d) Create a session bean Define the EJBHome and EJBObject interfaces and their methods Discuss the superclass for the home and remote interfaces Describe system and application exceptions Deploy and connect to a session bean

Creating the Enterprise Bean Class ejbCreate methods The SessionBean interface The EJBContext interface The SessionContext interface

Stateless and Stateful Session Beans Stateless session beans –Do not keep track of any information from one method call to the next Stateful session beans –Can change their state during a conversation with a client

Writing Business Methods for an Enterprise Bean Each EJB must declare the business methods that define the work that the EJB is designed to perform

The Home Interface Extends EJBHome Provides mechanisms to create and remove EJB components

The EJB Object Extends the EJBObject interface

Exceptions in EJB System exceptions Application exceptions

Example: A Session Bean The Teller bean class The Teller remote interface The Teller home interface

The Library Application The Book entity bean The Patron entity bean The CheckOutRecord entity bean The CheckOut session bean The CheckIn session bean

LibraryDB Schema

Introduction to EJB Deployment The deployment descriptor –DD XML tags Environment data –Environment property XML tags –Accessing environment data Using bean references –EJB reference XML tags –Using the EJB reference Using resource factories –Factory resource XML tags

Additional Deployment Concepts Assembler/deployer roles with the deployment descriptor EJB deployment in an EJB server

Summary Define the methods of the SessionBean interface Describe the EJBContext and the SessionContext interfaces Contrast stateful and stateless session beans Explain how to write business methods for a session bean Discuss the enterprise bean’s life cycle

Summary (cont’d) Create a session bean Define the EJBHome and EJBObject interfaces and their methods Discuss the superclass for the home and remote interfaces Describe system and application exceptions Deploy and connect to a session bean

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 4: Entity Beans

Objectives Discuss entity beans and their persistence management techniques Identify the methods of the EntityBean and EntityContext interfaces Define primary keys and their use Describe the mechanics involved in entity beans Use finder methods Write an entity bean and its required interfaces

What Is an Entity Bean? The EntityBean interface The EntityContext interface Primary keys

Entity Bean Architecture Creating entity beans Invoking business methods on entity beans Swapping entity beans Invoking remove( ) on an entity bean Life cycle of an entity bean instance

Life Cycle of an Entity Bean Instance

Bean-Managed Persistence Using JDBC Using a resource factory to connect to a database

Using Resource Factories

Entity Bean Methods The ejbCreate( ) method The ejbPostCreate( ) method The ejbRemove( ) method The ejbLoad( ) method The ejbStore( ) method

Using Finder Methods The ejbFindByPrimaryKey( ) method Multiple row finders

The Remote Interface All remote interfaces extend javax.ejb.EJBObject

The Home Interface The Account entity bean

Summary Discuss entity beans and their persistence management techniques Identify the methods of the EntityBean and EntityContext interfaces Define primary keys and their use Describe the mechanics involved in entity beans Use finder methods Write an entity bean and its required interfaces

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 5: Enterprise JavaBeans Clients

Objectives Use JNDI to obtain a reference to the home object Instantiate an EJB instance using the home object Call an enterprise bean's business methods Remove an enterprise bean Write an EJB client

Using JNDI

Creating an EJB Instance Invocation of business methods

Summary Use JNDI to obtain a reference to the home object Instantiate an EJB instance using the home object Call an enterprise bean's business methods Remove an enterprise bean Write an EJB client

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 6: Container-Managed Persistence

Objectives Discuss entity beans and CMP Explain the benefits and disadvantages of using CMP Describe the primary key as it relates to CMP Define an ejbCreate() method that uses CMP Write the requisite methods for an entity bean to use CMP

Introduction to Container- Managed Persistence (CMP) Benefits –Less code needed –Optimization techniques –More portable –Fewer bugs Disadvantages –Less flexibility –Inaccessible code

The Primary Key Primary key class –Must be serializable –Must be of a legal value type in RMI-IIOP

EJB Methods and CMP ejbCreate() ejbRemove() ejbLoad() ejbStore() Other methods Finder methods

The Deployment Descriptor EJB requirements DD XML tags

The Deployment Descriptor and CMP Example: A CMP entity bean –The EmployeeEJB bean class –The home interface –The remote interface

Summary Discuss entity beans and CMP Explain the benefits and disadvantages of using CMP Describe the primary key as it relates to CMP Define an ejbCreate() method that uses CMP Write the requisite methods for an entity bean to use CMP

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 7: Transactions in Enterprise JavaBeans

Objectives Define transactions and explain their use Distinguish transaction participants Define transaction properties Explain the EJB transactional model Describe distributed transactions Define transaction isolation levels Discuss EJB transaction attributes

What Are Transactions? Operations or series of operations that are treated as single units of work Transactional management

Participants in Transactions Transactional objects or applications Transaction managers Resources Resource managers

Properties of Transactions Atomicity Consistency Isolation Durability

EJB Transactional Models Flat transactional model Nested transactional model

Flat Transactional Model

Nested Transactional Model

Distributed Transactions Two-phase commits Transparent transaction control –Transaction context

Isolation Levels Strict –Each concurrent transaction is isolated from all other transactions Nonstrict –Increased transactional performance –Possibility of corrupted data

Transactions in EJB Transaction demarcation Container-managed transactions –Attributes Defining CMT in the DD Setting CMT in Deploytool

Container-Managed Transactions Container-managed transaction attributes Which methods require transaction attributes? The setRollbackOnly( ) and getRollbackOnly( ) methods Defining CMT in the DD Setting CMT in Deploytool

Bean-Managed Transactions UserTransaction interface –Properties –Methods Setting BMT in the DD BMT and stateful session beans BMT and stateless session beans

Summary Define transactions and explain their use Distinguish transaction participants Define transaction properties Explain the EJB transactional model Describe distributed transactions Define transaction isolation levels Discuss EJB transaction attributes

Copyright © 2002 ProsoftTraining. All rights reserved. Lesson 8: Enterprise JavaBeans Security

Objectives Define users in EJB security Discuss principals in EJB security Identify roles in EJB security Describe the DD’s role in EJB security Explain the EJB container’s role in EJB security

Defining Users, Principals and Roles Overview of EJB security –Authentication –Authorization Authorization in EJB code

Example: Users, Principals and Roles

Security and the Deployment Descriptor The bean developer and the DD The application assembler and the DD The deployer and the DD

Summary Define users in EJB security Discuss principals in EJB security Identify roles in EJB security Describe the DD’s role in EJB security Explain the EJB container’s role in EJB security

Enterprise JavaBeans Introduction to Server-Side Component Software Overview of the Enterprise JavaBeans Framework Creating Session Beans Entity Beans

Enterprise JavaBeans Enterprise JavaBeans Clients Container-Managed Persistence Transactions in Enterprise JavaBeans Enterprise JavaBeans Security