Chapter 4 Generating Hibernate Persistent Objects and JSF Pages

Hibernate Overview

Hibernate is an open source project developed by JBoss, which provides a powerful, high performance and transparent object/relational persistence and query solution for Java.

Hibernate lets you develop persistent objects using POJO (Plain Old Java Object). All the common Java idioms, including association, inheritance, polymorphism, composition, and the Java collections framework are supported. Hibernate allows you to express queries in its own portable SQL extension (HQL), as well as in native SQL, or with Java-based Criteria and Example objects.

PowerDesigner supports the design of Java classes, database schema and Object/Relational mapping (O/R mapping). Using these metadata, PowerDesigner can generate Hibernate persistent objects including:

• Persistent Java classes (domain specific objects)
• Configuration file
• O/R mapping files
• DAO factory
• Data Access Objects (DAO)
• Unit test classes for automated test
• JSF pages to allow users to manually test Hibernate objects

The following use cases are supported:

• Forward engineering – define classes, generate database schema and O/R mapping
• Reverse engineering – reverse engineer a database, generate classes and O/R mapping
• Meet-in-the-middle – manually define O/R mapping using the visual mapping editor

To generate persistent objects for Hibernate:

1. Create domain specific Java classes as usual.
2. Define O/R mapping.
3. Define Hibernate persistence options.
4. Generate Java code.
5. Compile the Java classes.
6. Run Hibernate unit tests and use JSF web pages to test Hibernate objects.

To use Hibernate persistent objects in your application:

1. Create a SessionFactory.
2. Connect to database.
3. Begin a transaction.
4. Work with the Java classes as usual (find objects, create new objects, modify objects, delete objects, etc.).
5. Commit the transaction.

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