barcode font vb.net Migrating CMP 2 entity beans to the EJB 3 JPA in Java

Generate Data Matrix 2d barcode in Java Migrating CMP 2 entity beans to the EJB 3 JPA

Migrating CMP 2 entity beans to the EJB 3 JPA
Creating ECC200 In Java
Using Barcode drawer for Java Control to generate, create Data Matrix 2d barcode image in Java applications.
www.OnBarcode.com
Data Matrix 2d Barcode Scanner In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
your entity classes because it will limit its usability to relying on the container. This boils down to a scenario where you cannot test or use it outside the container. We suggest that you take this opportunity to migrate such code to the service layer (i.e., the session fa ade). Finder and select methods If you ve used CMP entity beans in EJB 2, you know that finder and select methods are defined in the home interface for the entity bean as shown here:
Making UPC-A Supplement 5 In Java
Using Barcode encoder for Java Control to generate, create UPC Code image in Java applications.
www.OnBarcode.com
Linear 1D Barcode Encoder In Java
Using Barcode creation for Java Control to generate, create 1D Barcode image in Java applications.
www.OnBarcode.com
public interface UserLocalHome extends EJBLocalHome { User create() throws CreateException; User create(String userId, String firstName, String lastName, String userType) throws CreateException; User findByPrimaryKey(String primaryKey) throws FinderException; Collection findAll() throws FinderException; Collection findByFirstName(String name) throws FinderException; }
Drawing UPC Code In Java
Using Barcode creation for Java Control to generate, create UPC Code image in Java applications.
www.OnBarcode.com
QR Code JIS X 0510 Creator In Java
Using Barcode generator for Java Control to generate, create QR Code image in Java applications.
www.OnBarcode.com
Notice the two custom finders. The query for the finder methods (findAll and findByFirstName) are defined in the ejb-jar.xml using EJBQL as defined here:
Code39 Maker In Java
Using Barcode generator for Java Control to generate, create USS Code 39 image in Java applications.
www.OnBarcode.com
ISSN - 13 Generator In Java
Using Barcode generation for Java Control to generate, create International Standard Serial Number image in Java applications.
www.OnBarcode.com
<query> <query-method> <method-name>findById</method-name> <method-params/> </query-method> <ejb-ql>select object(o) from User o WHERE o.id = 1</ejb-ql> </query> <query> <query-method> <method-name>findByFirstName</method-name> <method-params> <method-param>java.lang.String</method-param> </method-params> </query-method> <ejb-ql> SELECT OBJECT(u) FROM User u WHERE u.firstName LIKE 1 </ejb-ql> </query>
Data Matrix ECC200 Generation In .NET
Using Barcode generation for Reporting Service Control to generate, create Data Matrix image in Reporting Service applications.
www.OnBarcode.com
Draw Data Matrix In Java
Using Barcode generator for Java Control to generate, create Data Matrix ECC200 image in Java applications.
www.OnBarcode.com
The finder methods and select methods in the bean class can be converted to named queries in the User entity class like so:
Creating Barcode In Visual C#.NET
Using Barcode creator for Visual Studio .NET Control to generate, create Barcode image in .NET framework applications.
www.OnBarcode.com
Creating Matrix In C#.NET
Using Barcode generation for .NET framework Control to generate, create Matrix image in .NET applications.
www.OnBarcode.com
@Entity @NamedQueries({ @NamedQuery(
Code-128 Creator In None
Using Barcode generation for Font Control to generate, create Code 128A image in Font applications.
www.OnBarcode.com
Barcode Generator In Visual Studio .NET
Using Barcode creation for ASP.NET Control to generate, create Barcode image in ASP.NET applications.
www.OnBarcode.com
Migrating to EJB 3
Painting Code-39 In Java
Using Barcode printer for BIRT reports Control to generate, create ANSI/AIM Code 39 image in BIRT reports applications.
www.OnBarcode.com
Printing UPC-A Supplement 5 In None
Using Barcode creation for Microsoft Excel Control to generate, create UPC-A image in Excel applications.
www.OnBarcode.com
name = "findUserById", query = "SELECT u FROM User u where u.id= 1" ), @NamedQuery( name = "findUserByFirstName", query = "SELECT u FROM User u WHERE u.firstName LIKE 1" )}) public class User implements Serializable { ... }
Barcode Recognizer In VS .NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Generate EAN128 In Java
Using Barcode creator for Android Control to generate, create EAN / UCC - 14 image in Android applications.
www.OnBarcode.com
While migrating the finder methods to named queries, we have changed the name of the named queries to unique names (findUserById from findById), because named queries are scoped for the persistence units. This is unlike finder methods that can be invoked only on an entity bean instance. You will notice that we have used the simplified syntax of a JPQL query. Optionally, you can migrate your query to an ad hoc or dynamic query in your session fa ade, but we recommend against that due to the performance reasons we discussed in chapter 13. Container-managed relationships In EJB 2.1, relationships are defined in deployment descriptors. Listing 14.5 shows the descriptor elements that define a unidirectional, one-to-one relationship between the User and ContactDetail entity beans, and a one-to-many relationship between the User and Bid entity beans.
Encode Code 128 In Visual Studio .NET
Using Barcode maker for Reporting Service Control to generate, create Code 128 image in Reporting Service applications.
www.OnBarcode.com
Create Data Matrix In Java
Using Barcode drawer for Android Control to generate, create Data Matrix ECC200 image in Android applications.
www.OnBarcode.com
Listing 14.5 Container-managed relationship defined in the deployment descriptor
<ejb-relation> <ejb-relationship-role> <ejb-relationship-role-name> Users may have one ContactDetail </ejb-relationship-role-name> <multiplicity>One</multiplicity> <relationship-role-source> Unidirectional one-to<ejb-name>User</ejb-name> one relationship </relationship-role-source> <cmr-field> <cmr-field-name>contact_contactUserId</cmr-field-name> </cmr-field> </ejb-relationship-role> </ejb-relation> <ejb-relation> <ejb-relation-name>Bids - Users</ejb-relation-name> <ejb-relationship-role> <ejb-relationship-role-name> Bids may have one User
Migrating CMP 2 entity beans to the EJB 3 JPA
</ejb-relationship-role-name> <multiplicity>Many</multiplicity> <relationship-role-source> Bidirectional one-to<ejb-name>Bids</ejb-name> many relationship </relationship-role-source> <cmr-field> <cmr-field-name>bidder</cmr-field-name> </cmr-field> </ejb-relationship-role> <ejb-relationship-role> <ejb-relationship-role-name> User may have many Bids </ejb-relationship-role-name> <multiplicity>One</multiplicity> <relationship-role-source> <ejb-name>User</ejb-name> </relationship-role-source> <cmr-field> <cmr-field-name>bids</cmr-field-name> <cmr-field-type>java.util.Collection</cmr-field-type> </cmr-field> </ejb-relationship-role> </ejb-relation>
The relationships need to be migrated to the entity class using the appropriate association annotations such as @OneToOne or @OneToMany. Note that we have used Java Generics and changed the association field to a Set from Collection type and such change will require appropriate changes in the client code. The simplified code looks like this:
@Entity public class User { @Id protected String userId; protected String email; @OneToOne protected ContactDetail contactDetail; @OneToMany(mappedBy = "bidder") protected Set<Bid> bids; ... } @Entity public class ContactDetail { @Id protected Long contactId; ... }
Migrating to EJB 3
@Entity public class Bid implements Serializable { @ManyToOne protected User bidder; ... }
In EJB 2, entity beans supported the concept of container-managed relationships. The container was automatically updating the reverse side of relationships when one side was updated. When migrating your relationships to EJB 3, you have to be aware that you are now responsible for managing both sides of your relationships. For example, if you had the following method in the User entity to update a relationship:
public addBid(Bid bid) { getBids.add(bid); }
you d have to change this code to add the back pointer (i.e., set the relationship from Bid to User) as follows:
public void addBid(Bid bid) { getBids().add(bid); bid.setUser(this); }
As you can see, there s not a lot of code involved, but the burden of keeping things bidirectional falls squarely on your shoulders now. Transactions and security settings CMP entity beans provided the ability to specify transactions and security settings for bean methods. In practice, these were rarely used in favor of the more popular session fa ade approach. EJB 3 entities don t provide such facilities, which means that you need to move security and transaction settings to your session fa ades.
Copyright © OnBarcode.com . All rights reserved.