Re: JPA+hibernate merge vs find fetching lazy collection
On Tue, 29 Dec 2009, Lew wrote:
Lew wrote:
Puzzle 1: Why are you explicitly allocating an ArrayList to
'objectsCfgSet'?
kamiseq wrote:
why not? and plus you dont need to check every time if collection is
null or not. this is not a problem here
Why not? Because it's atypical of JPA code and I haven't seen that
done. Usually you either let the JPA engine fill it
Which won't happen before the JPA provider has got its hands on it, so:
new GenObject().objectsCfgSet.add(something);
Will fail, right?
There's a general principle (more honoured in the breach than in the
observance) that JPA entities should be fully functional POJOs, ie should
work correctly even without JPA. Or, perhaps, that they *can* be, and
since this simplifies unit testing, some pundits elevate that to *should*.
or you fill it explicitly with the setter. For example,
<http://java.sun.com/developer/technicalArticles/J2EE/jpa/Customer.java>
They're using setters because they're using property access - note the @Id
annotation on the getCustomerID() method rather than the id field. That
means they have to use setters to set fields. Kamiseq is using field
access, which means he can access the fields directly. There's no
JPA-specific reason for him to use a setter rather than direct access.
tom
--
Remember Sammy Jankis.