jpa-2.0

I am using EclipseLink in my web application, and I am having a hard time gracefully catching and handling Exceptions it generates. I see from this thread what seems to be a similar problem, but I don't see how to work around or fix it. My code looks like this: public void persist(Category category) { try { utx.begin(); em.persist(category); utx.commit(); } catch (RollbackException ex) { // Log something } catch (HeuristicMixedException ex) { // Log something } catch (HeuristicRollbackException ex) { // Log something } catch (SecurityException ex) { // Log something } catch

I am using Hibernate as persistence provider and modelling my entities with JPA 2. Now a question came up and i hope you can help me. In my application you can open up a Game, create groups of players in it and walk around on the map (tiles (2d)). First my entity definitions: Game: @Entity public class Game implements Serializable { @Id @SequenceGenerator(name = "gen_gameid", sequenceName = "seq_gameid") @GeneratedValue(generator="gen_gameid") private long gameid; /** * Playing Characters. */ @OneToMany(mappedBy = "game") private List<Character> characters; private int round = 0; @OneToMany

I used EJB3/JPA when persisting my entities and I am happy on how it is able to manage my DB related task. My only concern is on the exception handling. My sample code when saving entity always comes in this flavor. Most of the tutorials that I read on the net comes in this flavor also with no regards to exception handling. @Stateless public class StudentFacade{ @PersistenceContext(unitName = "MyDBPU") private EntityManager em; public void save(Student student) { em.persist(student); } } But I dont know whats the best way of exception handling in an EJB app? What should be the best way when

Can anyone provide an example of how to write a case query using CriteriaBuilder ? What follows is a sample case expression using CriteriaBuilder (this works in JPA 2): Hashtable caseTable = new Hashtable(3); caseTable.put("Bob", "Bobby"); caseTable.put("Susan", "Susie"); caseTable.put("Eldrick", "Tiger"); Expression expression = builder.get("firstName").caseStatement(caseTable, "NoNickname").equal("Bobby"); It generates the following SQL query: "CASE t1.firstName WHEN 'Bob' THEN 'Bobby' WHEN 'Susan' THEN 'Susie' WHEN 'Eldrick' THEN 'Tiger' ELSE 'NoNickname' END = 'Bobby'" For more info please

i tried to observe JPA2 / Hibernate4 proxy behavior below, // Circular entity with lazy loading: @Entity public class Employee { @Id@Generated int id; String name; @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL) Employee boss; public String toString() { return id + "|" + name + "|" + boss; } //getters and setters ... } // Persist entities: // Outer entity: Employee employee = new Employee(); employee.setName("engineer"); // Inner entity: Employee boss = new Employee(); boss.setName("manager"); employee.setBoss(boss); entityTransaction.begin(); entityManager.persist(employee);

Is it possible to do cross database table joins in JPA? I have a users table in one database which has a foreign key to a organizations table in a separate database. Both the databases are on same physical machine. Now MySQL allows me to write queries which span across multiple databases, but I am not sure how to do this with JPA. The @Entity annotations on the Java POJO's don't take the name of the database so there is no way to mark a cross DB relationship. Is there a workaround for this situation? Perhaps using a native query to load the joined entity? We tried out the following approach