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JEE Programming

This presentation explores key concepts of the Java Persistence Query Language (JPQL) and essential design patterns such as Entity Access Object (EAO) and Session Façade in the context of Java EE programming. Topics include creating dynamic JPQL queries, utilizing named queries, and performing bulk update and delete operations. Additionally, it covers native SQL queries and result set mapping, demonstrating how these methods enhance data access while ensuring clean separation of business logic. Ideal for Java developers looking to deepen their understanding of persistence in enterprise applications.

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JEE Programming

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  1. INFORMATICS ENGINEERING – UNIVERSITY OF BRAWIJAYA Java Persistence API part 2 JEE Programming Eriq Muhammad Adams J eriq.adams@ub.ac.id

  2. Agenda • JPQL (Java Persistence Query Language) • EAO Pattern • Session Façade Pattern

  3. JPQL (Java Persistence Query Language) • Dynamic Query with JPQL • entityManager.createQuery(”select object o from Inventory o”).getResultList(); • Binding parameter : • entityManager.createQuery(”select object o from Inventory o where o.year=:year”).setParameter(”year”, year).getResultList(); • entityManager.createQuery(”select object o from Inventory o where o.year=?1”).setParameter(0, year).getResultList();

  4. JPQL (Java Persistence Query Language) (cont.) • Named Queries @Entity @NamedQueries({ @NamedQuery(name="findAllInventory", queryString="select object(o) from Inventory o"), @NamedQuery(name="findInventoryByYear", queryString="select object(o) from Inventory o where o.year=:year"), @NamedQuery(name="findInventoryByRegion", queryString="select object(o) from Inventory o where o.region=?1 ")}) public class Inventory implements Serializable{ ………

  5. JPQL (Java Persistence Query Language) (cont.) • entityManager.createNamedQuery(”findAllInventory”).getResultList(); • entityManager.createNamedQuery(”findInventoryByYear”).setParameter(”year”, year).getResultList(); • entityManager.createNamedQuery(”findInventoryByRegion”).setParameter(0, region).getResultList();

  6. JPQL (Java Persistence Query Language) (cont.) • Bulk Update and Delete Operation public intbulkDeleteEmptyInventory() { return em.createQuery("delete from Inventory o where o.quantity= 0").executeUpdate(); }

  7. JPQL (Java Persistence Query Language) (cont.) • Native SQL Query • entityManager.createNativeQuery(”select * from inventory”, entity.Inventory.class).getResultList(); • entityManager.createNativeQuery(”select * from inventory where year=?”,entity.Inventory.class ).setParameter(0, year).getResultList(); • Resultset Mapping • @SqlResultSetMapping(name = “InventoryResults", entities = @EntityResult(entityClass= Entity.Inventory.class)); • entityManager.createNativeQuery(”select * from inventory”, InventoryResults).getResultList();

  8. JPQL (Java Persistence Query Language) (cont.) • Native Named SQL Query @NamedNativeQuery( name = "findInventoryByYear", query = "SELECT * FROM inventory WHERE year = ?)", resultClass= entity.Inventory.class) @NamedNativeQuery( name = "findInventoryByYear", query = "SELECT * FROM inventory WHERE year = ?)", resultSetMapping = "InventoryResults") • entityManager.createNamedQuery(”findInventoryByYea r”).setParamater(0,year).getResultList();

  9. EAO Pattern • Stand for Entity Access Object Pattern • Separate or decouple data access with any business logic code. • It’s useful and widely used pattern because its reduce maintenance problem.

  10. EAO Pattern (cont.) • Illustration Sample Fig. taken from EJB 3 in Action, Manning

  11. Session Façade Pattern • The primary reasons the Session Façade pattern was invented was to reduce the number of remote calls for previous EJB incarnations, and this still holds true for EJB 3.

  12. Session Façade Pattern (cont.) • Illustration sample Fig. taken from EJB 3 in Action, Manning

  13. Demo • JPQL Demo in JPQLDemo.zip • EAO Pattern and Session Façade Pattern Demo in EAOSessionFacade.zip

  14. References • EJB 3 in Action, Manning • Beginning EJB 3 Application Development, Apress

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