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From "Kevin Sutter" <kwsut...@gmail.com>
Subject Re: Eager fetching not working with enums and lobs
Date Mon, 09 Jul 2007 02:06:52 GMT
Craig,
Comments below...

On 7/7/07, Craig L Russell <Craig.Russell@sun.com> wrote:
>
> Hi Kevin,
>
> If you can figure out what the spec (9.1.18 and 9.1.19) sez, my hat's
> off to you. What a mudbake this is.


Isn't that just standard order of business with these specs?  :-)

Part of the issue is the annotation definition. If @Basic is
> specified, and the user doesn't explicitly override the fetch type,
> it appears to our annotation processor as if the user specified
> EAGER. Even if @Basic is used with @Lob, if lazy is wanted, it has to
> be explicitly stated.


That's how I read the spec.  The first paragraph of 9.1.18 indicates that
@Basic can be applied to any those types (enums and lob types included).
The default fetchType is EAGER.  It also states that @Basic is optional.
So, the way I read this is that we should be doing EAGER fetching for all of
those listed types unless explicitly told to do otherwise via the LAZY
fetchType via an @Basic annotation.

Maybe we should discuss @Lob in more detail. It isn't obvious to me
> that @Basic can always be used and we might have an option to choose
> a better default for the fetch behavior if @Basic annotation is omitted.


It seems to me that the spec is clear on the use and expectations of @Basic
and the default fetchType of EAGER.  Unless there are other spec references
that contradict the statements in 9.1.18...

Craig
>
> On Jul 6, 2007, at 11:37 AM, Kevin Sutter wrote:
>
> > I guess the spec is a bit clearer on this than I first thought.
> > Section
> > 9.1.8 of the JPA spec indicates that @Basic is optional and applies
> > to the
> > following types:
> >
> > "..Java primitive types, wrappers of the primitive types,
> > java.lang.String,
> > java.math.BigInteger,
> > java.math.BigDecimal, java.util.Date, java.util.Calendar,
> > java.sql.Date,
> > java.sql.Time, java.sql.Timestamp, byte[], Byte[], char[], Character
> > [],
> > enums, and any other type that implements Serializable."
> >
> > And, since the default fetch type for @Basic is EAGER, it looks
> > like we need
> > to do eager fetching for both @Enumerated and @Lob fields unless
> > otherwise
> > overridden by a LAZY fetch type (ie. @Basic(fetch=LAZY)).  Agree?
> >
> > Kevin
> >
> > On 7/6/07, Craig L Russell <Craig.Russell@sun.com> wrote:
> >>
> >>
> >> On Jul 6, 2007, at 10:52 AM, Patrick Linskey wrote:
> >>
> >> > The spec doesn't seem to discuss it, but I think that lazy is a
> >> pretty
> >> > good default behavior for @Lob field types -- typically @Lob things
> >> > are big, so you often don't want them in the default fetch graph.
> >>
> >> Enum is different, though. Enum should be eager fetching by default.
> >>
> >> Lazy fetching is optional, so we can decide what we want to do. It
> >> seems that the existence of @Basic should not change our strategy.
> >> And we should default to lazy fetching for Lob and eager fetching for
> >> Enum.
> >>
> >> Craig
> >> >
> >> > -Patrick
> >> >
> >> > On 7/6/07, Kevin Sutter <kwsutter@gmail.com> wrote:
> >> >> I am finding that the supposed default action of Eager fetching is
> >> >> not
> >> >> happening with @Enumerated and @Lob fields.  If I explicitly
> >> >> specify the
> >> >> @Basic annotation, then the fields are eagerly fetched.  But,
> >> >> without this
> >> >> extraneous @Basic, these fields are lazily loaded.  This action
> >> >> does not
> >> >> seem to be consistent with the spec.  Nor, can I find any mention
> >> >> of this
> >> >> alternate behavior in our OpenJPA manual.  Sounds like a bug to
> >> >> me.  Any
> >> >> other insights?
> >> >>
> >> >> This works (eager loading kicks in):
> >> >>
> >> >>     @Basic @Enumerated(EnumType.STRING)
> >> >>     private Gender gender;
> >> >>
> >> >> This does not work (lazy loading kicks in):
> >> >>
> >> >>     @Enumerated(EnumType.STRING)
> >> >>     private Gender gender;
> >> >>
> >> >> I have also tried to use defaults (without any annotations),
> >> and lazy
> >> >> loading still kicks in:
> >> >>
> >> >>     private Gender gender;
> >> >>
> >> >> Thanks,
> >> >> Kevin
> >> >>
> >> >
> >> >
> >> > --
> >> > Patrick Linskey
> >> > 202 669 5907
> >>
> >> Craig Russell
> >> Architect, Sun Java Enterprise System http://java.sun.com/products/
> >> jdo
> >> 408 276-5638 mailto:Craig.Russell@sun.com
> >> P.S. A good JDO? O, Gasp!
> >>
> >>
> >>
>
> Craig Russell
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> 408 276-5638 mailto:Craig.Russell@sun.com
> P.S. A good JDO? O, Gasp!
>
>
>

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