Re: [hibernate-dev] Attribute paths and '.' versus '#' as separator

2014-03-29 17:40 GMT+01:00 Steve Ebersole <steve(a)hibernate.org&gt;: To wrap this up.. > > The most important part for me is being able to identify the point between > the "attribute base" and the "attribute path". If we just use a separate > delimiter there, that's enough for me. Since one of us has a preference > for using dots within the "attribute path" part (and its irrelevant to > me), > I'll go with that. So: > > org.h.SomeEntity#nv.to.hell > +1 for that. You might also consider to use "::" as the delimiter between base and path: org.h.SomeEntity::nv.to.hell "::" is the syntax for method references in Java 8 and it may possibly be used for field references as well in a future Java version. So in some way it may be nice to resemble that. --Gunnar > > > > On Fri, Mar 28, 2014 at 3:18 PM, Steve Ebersole <steve(a)hibernate.org&gt; > wrote: > > > What we choose as a separator after the "pivot" is irrelevant to a > degree, > > especially in terms of the compatibility concern. I think you > understood > > that, just being clear. Meaning that calls like: > > > > sessionFactoryImplementor.getCollectionPersister( > "org.h.SomeEntity.nv.to.hell" > > ) > > > > will fail whether we use "org.h.SomeEntity#nv.to.hell" or > "org.h.SomeEntity#nv#to#hell" > > as the role key. > > > > As for "being natural", we'll agree to disagree. But Java has no such > > notion as attributes so arguing about what is more natural in how Java > > represents attribute paths is a bit moot imo. Were these all > *accessible > > fields*, then sure the code to access them chained would use 'dots'. > But I > > think its pretty plain to see how in the call I listed above: > > > > sessionFactoryImplementor.getCollectionPersister( > "org.h.SomeEntity.nv.to.hell" > > ) > > > > the use of '.' locks you into never being able to programatically > > parse/understand that String structural, which I think is just very > > limiting in many places. > > > > > > > > On Fri, Mar 28, 2014 at 1:44 PM, Emmanuel Bernard < > emmanuel(a)hibernate.org&gt;wrote: > > > >> No strong feeling about it. > >> It will break the OGM dialects that make use of the collection role > >> though. So we need to anticipate. > >> > >> To me . looks more like the code being used and is a natural notation > >> even beyond Java. But I get that # offers some additional info. > >> Have you considered? > >> > >> org.h.SomeEntity#nv.to.hell > >> > >> I think that would have my preference actually. > >> > >> On 27 Mar 2014, at 23:54, Steve Ebersole <steve(a)hibernate.org&gt; wrote: > >> > >> > This is a bit of a potentially insidious one. Not the best way to > start > >> > off a discussion, I know :) > >> > > >> > The premise is this... Until now Hibernate has represented attribute > >> roles > >> > using dots. For an attribute named 'department' on the > >> com.acme.Employee > >> > entity, the role would be "com.acme.Employee.department". In terms > of > >> > embeddables, say Employee had an 'address' embedded with its own > >> attributes > >> > like 'city'. Then, the full role for 'city' would be > >> > "com.acme.Employee.address.city". > >> > > >> > As you can start to see the dots here are completely > indistinguishable > >> in > >> > terms of those which define the package/class and those which > identify > >> the > >> > attribute "path". > >> > > >> > So one of the things I started playing with in 5 is to replace the > >> > separators used in attribute paths to use '#', such that > >> > "com.acme.Employee.address.city" would instead be > >> > "com.acme.Employee#address#city". This makes the role fully > parseable > >> > which is actually useful in quite a few situations. And it REALLY > >> helps in > >> > things I have just started working on like storing metadata for > >> composites > >> > (embeddeds/embeddables) on the SessionFactory, which is the first > step > >> in > >> > support for some cool new features around embeddables like > discriminated > >> > inheritance support. > >> > > >> > However, there is a minor drawback. Like all attributes, collections > >> have > >> > a role. Unfortunately the use of '.' in their role Strings leaks > into > >> the > >> > SPI in terms of locating the CollectionPersisters. > >> > > >> > So the question is whether to continue with this path of replacing > the > >> use > >> > of '.' with '#' for attribute path separators. The drawback is > >> > unfortunate. The benefit is very nice, but I can't really say it is > >> > required atm. > >> > > >> > Votes? Thoughts? > >> > _______________________________________________ > >> > 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 >