Re: [hibernate-dev] Another @Access quandry

My point is that I do not find annotating a getter method with @Access(FIELD) to be inherently common sense. It really boils down to the purpose/intent of @Access. If @Access *at the attribute level* is ultimately *just* indicating how to extract/inject then I think @Access(FIELD) on the getter does make sense. If @Access *at the attribute level* also directs where to look for annotations (consistent with @Access at class/hierarchy-level) then I think @AccessFile needs to be on the field along with the other annotations, assuming we stay with non-mixed placement for an attribute.

So let's decide that first. Since the spec does not say clearly one way or the other, I guess we have some leeway here. https://hibernate.atlassian.net/browse/HHH-9085 (Introduce @IdGetter and @IdSetter) plays in here as well. On Wed, Mar 26, 2014 at 11:21 AM, Emmanuel Bernard <emmanuel(a)hibernate.org&gt; wrote: > > My take on the spec as always been that I'd rather follow the intent, > the common sense above the letter. Likewise, I favored user experience > over spec strict adherence. > I did clash numerous time with the TCK in these targets but I still > prefer that over just doing something stupid but spec to the letter. > (this is general and not specific to that case). > > Anyway so my take is pretty much as it was when I first implemented > @AccessType even if it steps over the spec at the margin. > BTW I'm also happy if we all decide I made a usability mistake that should > be fixed. > > Emmanuel > > On Wed 2014-03-26 11:14, Steve Ebersole wrote: > > On Wed, Mar 26, 2014 at 10:12 AM, Steve Ebersole > > <steve(a)hibernate.org&gt;wrote: > > > > > It does violate the spec though, that's the problem: > > > > > > > Well it *could* be read to violate the spec. That's inherently the > > problem > > with specs that use unclear wording; they can be read and argued > > multiple > > ways. > > > > > > > > > > > > "... It is not permitted to specify a field as Access(PROPERTY) or a > > > property as Access(FIELD)..." > > > > > > which imo is exactly what this is doing (specifying a property as > > > FIELD): > > > > > > @Id > > > @GeneratedValue > > > @Access(AccessType.FIELD) > > > public long getId() { > > > return id; > > > } > > > > > > > > > > > > On Wed, Mar 26, 2014 at 9:56 AM, Sanne Grinovero > > > <sanne(a)hibernate.org&gt;wrote: > > > > > >> I do of course agree that people should use a single strategy and > > >> stick to it, so I agree with your reading about what the "general > > >> expectation" is. > > >> > > >> But the original test represents a quite naturally looking example > > >> and > > >> it's hard to justify why that should be considered illegal; I'd > > >> probably be more inclined in making user's life easier than try to > > >> lecture them about how a proper mapping should look like. > > >> > > >> Ignoring any annotation leads to waste of time and debugging > > >> frustration, so rather than silently discarding a mis-positioned > > >> annotation I'd prefer a fail-fast approach; that said I think just > > >> applying them all - as long as there are no obvious conflicting > > >> annotations - would be even more user friendly and doesn't seem to > > >> violate any specific wording of the spec. > > >> > > >> Sanne > > >> > > >> > > >> On 26 March 2014 13:57, Steve Ebersole <steve(a)hibernate.org&gt; wrote: > > >> > Again from the spec (still discussing class-level Access(PROPERTY)) > > >> > : > > >> "The > > >> > behavior is undefined if mapping annotations are placed on any > > >> > instance > > >> > variables defined by the class for which Access(FIELD) is not > > >> specified". > > >> > > > >> > Which to me implies that the expectation for switching access for a > > >> > particular field within such a class is to annotate the *field* > > >> > with > > >> > Access(FIELD). > > >> > > > >> > Also the footnote to this sections seems very relevant: > > >> > > > >> > "[8] ... It is not permitted to specify a field as Access(PROPERTY) > > >> > or a > > >> > property as Access(FIELD)..." > > >> > > > >> > > > >> > > > >> > On Wed, Mar 26, 2014 at 8:02 AM, Emmanuel Bernard < > > >> emmanuel(a)hibernate.org&gt; > > >> > wrote: > > >> >> > > >> >> My reading at the time and what I did find more intuitive is what > > >> >> the > > >> >> test represents. > > >> >> > > >> >> Entity level @AccessType expresses where the annotations should > > >> >> be. Otherwise the position of @Id is used to find the access type > > >> >> to > > >> >> consider annotation wise. > > >> >> > > >> >> If for a few attributes I wish to use the alternative property > > >> >> access, > > >> I > > >> >> can add @AccessType next to the other annotations but expressing > > >> >> that > > >> >> the actual property value access is based on the alternative > > >> >> access. > > >> >> That way, all annotations are in the same place. > > >> >> > > >> >> On Wed 2014-03-26 11:12, Sanne Grinovero wrote: > > >> >> > As a user I would not expect the @Access annotation to be > > >> >> > treated as > > >> a > > >> >> > special case by the framework in terms of when an annotation is > > >> >> > ignored, as for example that I can put this on either properties > > >> >> > or > > >> >> > fields, and it would not be ignored, while other annotations > > >> >> > could be > > >> >> > ignored depending on the position. > > >> >> > > > >> >> > Also I highly doubt that there is a practical use case to > > >> >> > "comment" a > > >> >> > mapping annotation by moving it to the wrong position (say I > > >> >> > move a > > >> >> > @GeneratedValue from a field to a property when using FIELD > > >> >> > access): > > >> >> > that would be extremely confusing to maintain. > > >> >> > > > >> >> > The spec's wording states "When Access(PROPERTY) is applied to > > >> >> > an > > >> >> > [...] mapping annotations **may** be placed on .." > > >> >> > I'd stress that it doesn' t say "must" but "may", and also > > >> >> > doesn't > > >> >> > seem to strictly ban the opposite. > > >> >> > > > >> >> > As a user if I put a mapping annotation anywhere I expect it to > > >> >> > be > > >> >> > respected, so I would expect the framework to work on the union > > >> >> > of > > >> the > > >> >> > possible positions, and probably even to throw an exception on > > >> >> > conflicting options. The @Access property would then only be > > >> >> > used to > > >> >> > state which access strategy should be used (and a nice effect is > > >> >> > tha > > >> >> > the name becomes particularly self-explanatory too). > > >> >> > > > >> >> > Also there are many types of possible contradictions in the > > >> >> > mapping > > >> >> > options: > > >> >> > > > >> >> > public class Course { > > >> >> > @Id @GeneratedValue(strategy=TABLE) > > >> >> > private long id; > > >> >> > ... > > >> >> > > > >> >> > @Id @GeneratedValue(strategy=SEQUENCE) > > >> >> > public long getId() { > > >> >> > return id; > > >> >> > } > > >> >> > > > >> >> > Or you could have a stronger conflict which isn't solvable via > > >> >> > AccesType "rules" either: > > >> >> > > > >> >> > public class Course { > > >> >> > @Id @GeneratedValue(strategy=TABLE) > > >> >> > @Access(AccessType.FIELD) > > >> >> > private long id; > > >> >> > ... > > >> >> > > > >> >> > @Id @GeneratedValue(strategy=SEQUENCE) > > >> >> > @Access(AccessType.PROPERTY) > > >> >> > public long getId() { > > >> >> > return id; > > >> >> > } > > >> >> > > > >> >> > This last example is the reason why I think you should always > > >> >> > consistently look at both to collect mapping options, and > > >> >> > possibly > > >> >> > throw runtime exceptions. > > >> >> > > > >> >> > Sanne > > >> >> > > > >> >> > > > >> >> > > > >> >> > > > >> >> > On 26 March 2014 04:13, Steve Ebersole <steve(a)hibernate.org&gt; > > >> >> > wrote: > > >> >> > > >From the test > > >> >> > > > > >> >> > > > > >> > > >> org.hibernate.test.annotations.access.jpa.AccessMappingTest#testExplicitPropertyAccessAnnotationsWithHibernateStyleOverride > > >> >> > > we have the following: > > >> >> > > > > >> >> > > > > >> >> > > @Entity > > >> >> > > @Access(AccessType.PROPERTY) > > >> >> > > public class Course3 { > > >> >> > > private long id; > > >> >> > > ... > > >> >> > > > > >> >> > > @Id > > >> >> > > @GeneratedValue > > >> >> > > @Access(AccessType.FIELD) > > >> >> > > public long getId() { > > >> >> > > return id; > > >> >> > > } > > >> >> > > ... > > >> >> > > } > > >> >> > > > > >> >> > > The test asserts that this is a valid mapping. Granted that > > >> >> > > the > > >> spec > > >> >> > > is > > >> >> > > very unclear here, so I might be missing something. The > > >> >> > > pertinent > > >> >> > > spec > > >> >> > > section here states: > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> >> > > *<quote>When Access(PROPERTY) is applied to an entity class, > > >> >> > > mapped > > >> >> > > superclass, or embeddableclass, mapping annotations may be > > >> >> > > placed > > >> on > > >> >> > > the > > >> >> > > properties of that class, and the persistenceprovider runtime > > >> accesses > > >> >> > > persistent state via the properties defined by that class. All > > >> >> > > proper-ties > > >> >> > > that are not annotated with the Transient annotation are > > >> persistent. > > >> >> > > WhenAccess(PROPERTY) is applied to such a class, it is > > >> >> > > possible to > > >> >> > > selectively designate indi-vidual attributes within the class > > >> >> > > for > > >> >> > > instance > > >> >> > > variable access. To specify a persistent instancevariable for > > >> access > > >> >> > > by the > > >> >> > > persistence provider runtime, that instance variable must be > > >> >> > > desig-nated > > >> >> > > Access(FIELD).</quote>* > > >> >> > > > > >> >> > > > > >> >> > > I can see a few different ways to read that: > > >> >> > > > > >> >> > > 1) @Access can be placed on the attribute to define both where > > >> >> > > to > > >> look > > >> >> > > for > > >> >> > > mapping annotations and the runtime access strategy for a > > >> >> > > given > > >> >> > > attribute. > > >> >> > > Here, we'd do: > > >> >> > > > > >> >> > > @Entity > > >> >> > > @Access(AccessType.PROPERTY) > > >> >> > > public class Course3 { > > >> >> > > @Id > > >> >> > > @GeneratedValue > > >> >> > > @Access(AccessType.FIELD) > > >> >> > > private long id; > > >> >> > > ... > > >> >> > > > > >> >> > > public long getId() { > > >> >> > > return id; > > >> >> > > } > > >> >> > > ... > > >> >> > > } > > >> >> > > > > >> >> > > 2) @Access can be placed on the attribute to define the > > >> >> > > runtime > > >> access > > >> >> > > strategy for a given attribute, but the class/hierarchy > > >> >> > > AccessType > > >> >> > > controls > > >> >> > > where to look for mapping annotations. This would lead to: > > >> >> > > > > >> >> > > @Entity > > >> >> > > @Access(AccessType.PROPERTY) > > >> >> > > public class Course3 { > > >> >> > > @Access(AccessType.FIELD) > > >> >> > > private long id; > > >> >> > > ... > > >> >> > > > > >> >> > > @Id > > >> >> > > @GeneratedValue > > >> >> > > public long getId() { > > >> >> > > return id; > > >> >> > > } > > >> >> > > ... > > >> >> > > } > > >> >> > > > > >> >> > > The test seems to illustrate that our legacy code made yet a > > >> >> > > 3rd > > >> >> > > reading of > > >> >> > > this passage such that @Access is still considered a "mapping > > >> >> > > annotation" > > >> >> > > even though that seems to directly contradict "To specify a > > >> persistent > > >> >> > > instance > > >> >> > > variable for access by the persistence provider runtime, that > > >> instance > > >> >> > > variable must be desig- > > >> >> > > nated Access(FIELD)." > > >> >> > > > > >> >> > > > > >> >> > > Is there some other passage I am missing that bears on what to > > >> >> > > do > > >> >> > > here? > > >> >> > > How do y'all feel about that passage and its implications on > > >> >> > > this > > >> >> > > test > > >> >> > > mapping? > > >> >> > > _______________________________________________ > > >> >> > > hibernate-dev mailing list > > >> >> > > hibernate-dev(a)lists.jboss.org > > >> >> > > https://lists.jboss.org/mailman/listinfo/hibernate-dev > > >> >> > _______________________________________________ > > >> >> > hibernate-dev mailing list > > >> >> > hibernate-dev(a)lists.jboss.org > > >> >> > https://lists.jboss.org/mailman/listinfo/hibernate-dev > > >> > > > >> > > > >> > > > > > >