FindingNewObjects

A common TopLink problem is creating a new object through the UOW, and wanting to access it later (before commit). Because the object is new, it doesn't have a primary key yet, and one is therefore unable to look it up.

Person personClone = (Person) uow.newInstance(Person.class);
personClone.setId(1);
personClone.setName("me");
 
// uow.commit();  --- not committed
 
ExpressionBuilder builder = new ExpressionBuilder();
Expression expr = builder.get("name").equal("me");
Person personFound = (Person) session.readObject(Person.class, expr);
// personFound is null 

Possible solutions:

1. assign the object a primary key right away, with UOW#assignSequenceNumber
2. use a conforming query that will search the UOW, see ConformResultsInUnitOfWork
3. pass the new object around using a property:

session.setProperty("NEW PERSON", personClone);
// later 
Person newPerson = (Person) session.getProperty("NEW PERSON");

See Also

forum:280729, forum:240825

The UnitOfWorkPrimer discusses this trick also.