Exercise 5.3: The Local Component Interfaces
by Richard Monson-Haefel, Bill Burke, Sacha Labourey
Enterprise JavaBeans, Fourth Edition
- Enterprise JavaBeans, 4th Edition
- Preface
- I. Lay of the Land
- 1. Introduction
- 2. Architectural Overview
- 3. Resource Management and the Primary Services
- 4. Developing Your First Enterprise Beans
- Choosing and Setting Up an EJB Server
- Developing an Entity Bean
- Developing a Session Bean
- 5. The Remote and Local Client View
- 6. CMP: Basic Persistence
- 7. CMP: Entity Relationships
- The Seven Relationship Types
- Abstract Persistence Schema
- Database Modeling
- One-to-One, Unidirectional Relationship
- One-to-One, Bidirectional Relationship
- One-to-Many, Unidirectional Relationship
- The Cruise, Ship, and Reservation EJBs
- Many-to-One, Unidirectional Relationship
- One-to-Many, Bidirectional Relationship
- Many-to-Many, Bidirectional Relationship
- Many-to-Many, Unidirectional Relationship
- Co-Location and the Deployment Descriptor
- Cascade Delete and Remove
- The Seven Relationship Types
- 8. CMP: EJB QL
- Declaring EJB QL
- The Query Methods
- EJB QL Examples
- Simple Queries
- Simple Queries with Paths
- The IN Operator
- Using DISTINCT
- The WHERE Clause and Literals
- The WHERE Clause and Input Parameters
- The WHERE Clause and Operator Precedence
- The WHERE Clause and CDATA Sections
- The WHERE Clause and Arithmetic Operators
- The WHERE Clause and Logical Operators
- The WHERE Clause and Comparison Symbols
- The WHERE Clause and Equality Semantics
- The WHERE Clause and BETWEEN
- The WHERE Clause and IN
- The WHERE Clause and IS NULL
- The WHERE Clause and IS EMPTY
- The WHERE Clause and MEMBER OF
- The WHERE Clause and LIKE
- Functional Expressions
- EJB 2.1: The ORDER BY Clause
- Problems with EJB QL
- 9. Bean-Managed Persistence
- 10. The Entity-Container Contract
- The Primary Key
- The Callback Methods
- ejbHome( )
- EntityContext
- The Life Cycle of an Entity Bean
- Does Not Exist
- The Pooled State
- The Ready State
- Transitioning from the Pooled state to the Ready state via creation
- Transitioning from the Pooled state to the Ready state via a query method
- Transitioning from the Pooled state to the Ready state via activation
- Transitioning from the Ready state to the Pooled state via passivation
- Transitioning from the Ready state to the Pooled state via removal
- Life in the Ready State
- End of the Life Cycle
- 11. Session Beans
- The Stateless Session Bean
- The ProcessPayment EJB
- The database table (PAYMENT)
- The remote interface (ProcessPaymentRemote)
- Dependent objects (CreditCardDO and CheckDO classes)
- An application exception (PaymentException)
- The home interface (ProcessPaymentHomeRemote)
- The bean class (ProcessPaymentBean)
- Accessing environment properties (JNDI ENC)
- The ProcessPayment EJB’s deployment descriptor
- Local component interfaces
- The ProcessPayment EJB
- The Life Cycle of a Stateless Session Bean
- The Stateful Session Bean
- Getting Set Up for the TravelAgent EJB
- The TravelAgent EJB
- The remote interface (TravelAgent)
- Dependent object (TicketDO)
- The home interface (TravelAgentHomeRemote)
- Taking a peek at the client view
- TravelAgentBean: The bean class
- JNDI ENC and EJB references
- Remote EJB references in the JNDI ENC
- Local EJB references in the JNDI ENC
- The bookPassage( ) method
- Why use a Reservation entity bean?
- Listing behavior (listAvailableCabins( ))
- The TravelAgent deployment descriptor
- The Life Cycle of a Stateful Session Bean
- The Stateless Session Bean
- 12. Message-Driven Beans
- JMS and Message-Driven Beans
- JMS-Based Message-Driven Beans
- The Life Cycle of a Message-Driven Bean
- Connector-Based Message-Driven Beans
- EJB 2.1: Message Linking
- 13. Timer Service
- 14. EJB 2.1: Web Service Standards
- 15. EJB 2.1 and Web Services
- 16. Transactions
- ACID Transactions
- Declarative Transaction Management
- Isolation and Database Locking
- Nontransactional Beans
- Explicit Transaction Management
- Exceptions and Transactions
- Transactional Stateful Session Beans
- 17. J2EE
- 18. XML Deployment Descriptors
- The ejb-jar File
- The Contents of a Deployment Descriptor
- The Document Headerand Schema Declarations
- The Descriptor’s Body
- Describing Enterprise Beans
- Describing Relationships
- Describing Bean Assembly
- 19. EJB Design in the Real World
- II. JBoss Workbook
- 20. Introduction
- 21. JBoss Installation and Configuration
- 22. Exercises for Chapter 4
- 23. Exercises for Chapter 5
- 24. Exercises for Chapter 6
- 25. Exercises for Chapter 7
- 26. Exercises for Chapter 8
- 27. Exercises for Chapter 9
- 28. Exercises for Chapter 11
- 29. Exercises for Chapter 12
- Exercise 12.1: JMS as a Resource
- Exercise 12.2: The Message-Driven Bean
- 30. Exercises for Chapter 13
- 31. Exercises for Chapter 15
- A. Database Configuration
- Index
- Colophon
The example program in Exercise 5.3 explores the use of local interfaces. The Cabin entity bean you created in Exercise 4.1 will be expanded to provide a local interface for use in the TravelAgent stateless session bean. This exercise also describes how to modify your EJB deployment descriptors to enable local interfaces.
If you already have JBoss running, there is no reason to restart it. Otherwise, start it up as instructed in the JBoss Installation and Configuration chapter.
The database should contain the 100 rows created by a successful
execution of the test programs from Exercise
4.1.
In the ex05_3 directory, build and deploy the
examples as you did for Exercise 5.1.
JBoss has a minor restriction. It requires that you use
<ejb-link> when you want your bean to
reference a local bean through an
<ejb-local-ref> tag.
<ejb-jar>
<enterprise-beans>
...
<session>
<ejb-name>TravelAgentEJB</ejb-name>
<home>com.titan.travelagent.TravelAgentHomeRemote</home>
<remote>com.titan.travelagent.TravelAgentRemote</remote>
<ejb-class>com.titan.travelagent.TravelAgentBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
<ejb-local-ref>
<ejb-ref-name>ejb/CabinHomeLocal</ejb-ref-name>
<ejb-ref-type>Entity</ejb-ref-type>
<local-home>com.titan.cabin.CabinHomeLocal</local-home>
<local>com.titan.cabin.CabinLocal</local>
<!-- ejb-link is required by jboss for local-refs. -->
<ejb-link>CabinEJB</ejb-link>
</ejb-local-ref>
...
</ejb-jar>If you examine the jboss.xml file for Exercise
5.3, you’ll see that you must also declare the JNDI
binding for the remote home interface. The Cabin
EJB’s local home interface doesn’t
need a binding in jboss.xml, though, because the
binding information is contained in the
<ejb-link> tag instead. JBoss will register
both CabinHomeRemote and
CabinHomeLocal into the JNDI tree.
<jboss>
<enterprise-beans>
<entity>
<ejb-name>CabinEJB</ejb-name>
<jndi-name>CabinHomeRemote</jndi-name>
<local-jndi-name>CabinHomeLocal</local-jndi-name>
</entity>
TravelAgentEJB only tells JBoss under which JNDI
name it should be bound:
<session>
<ejb-name>TravelAgentEJB</ejb-name>
<jndi-name>TravelAgentHomeRemote</jndi-name>
</entity>
</enterprise-beans>
</jboss>The example code for
Client_53
is exactly the same as Client_3 from Exercise
4.2.
Run Client_53 by invoking the appropriate Ant
task, as you did in previous examples:
run.client_53. Remember to set your
JBOSS_HOME and PATH environment
variables.
The output should look something like this:
C:workbookex05_3>ant run.client_53
Buildfile: build.xml
prepare:
compile:
ejbjar:
run.client_53:
[java] 1,Master Suite,1
[java] 3,Suite 101,1
[java] 5,Suite 103,1
[java] 7,Suite 105,1
[java] 9,Suite 107,1
[java] 12,Suite 201,2
[java] 14,Suite 203,2
[java] 16,Suite 205,2
[java] 18,Suite 207,2
[java] 20,Suite 209,2
[java] 22,Suite 301,3
[java] 24,Suite 303,3
[java] 26,Suite 305,3
[java] 28,Suite 307,3-
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