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From John Huss <johnth...@gmail.com>
Subject Re: [jira] [Created] (CAY-1724) Add 'Property' class for easier and better Expression creation
Date Wed, 08 Aug 2012 18:52:50 GMT
On Wed, Aug 8, 2012 at 12:34 PM, Andrus Adamchik <andrus@objectstyle.org>wrote:

> I am now experimenting with the new class generation too. Since Property
> is simply a singleton wrapper of a String name, it is pretty lightweight
> IMO.
>
> But now I am wondering whether we still need String constants for property
> names? My main use of those was always when building qualifiers. Now this
> will be handled via Properties. Besides you can do MY_PROP.getName().
>
> So do we need this extra redundancy in declarations, making the class less
> readable? Or should we just keep the Property kind?
>

I would vote for deprecating and then removing the string constants.

Have you thought about including multiple revisions of the templates to
allow people to stick with older ones if they want to?  Or are they
responsible for finding the old file in the source and putting in their app
if they don't want to change?

John

On Aug 3, 2012, at 4:57 AM, Michael Gentry wrote:
> > I'm a bit delayed and just saw this ...
> >
> > I'm curious how much extra overhead this will add to each Cayenne
> > class?  Probably not a huge issue since it is declared statically, but
> > I'm still curious.
> >
> > Thanks,
> >
> > mrg
> >
> >
> > On Wed, Jul 11, 2012 at 3:04 AM, Andrus Adamchik <andrus@objectstyle.org>
> wrote:
> >> +1. I saw it used on one project and it was a nice concept.
> >>
> >> Andrus
> >>
> >> On Jul 11, 2012, at 7:30 AM, John Huss (JIRA) wrote:
> >>
> >>> John Huss created CAY-1724:
> >>> ------------------------------
> >>>
> >>>           Summary: Add 'Property' class for easier and better
> Expression creation
> >>>               Key: CAY-1724
> >>>               URL: https://issues.apache.org/jira/browse/CAY-1724
> >>>           Project: Cayenne
> >>>        Issue Type: Improvement
> >>>        Components: Core Library
> >>>  Affects Versions: 3.2M1
> >>>          Reporter: John Huss
> >>>          Priority: Minor
> >>>       Attachments: Property.java
> >>>
> >>> Project Wonder (WebObjects) has a class which is basically just a
> wrapper around an attribute or relationship name that gives you a way to
> create Expressions in type-safe manner and with minimal effort.  Also sort
> orderings can be easily generated.  In Wonder, these "property" objects are
> part of the entity template so they are generated automatically.
> >>>
> >>> So for example:
> >>>
> >>> public class _Artist extends CayenneDataObject {
> >>>  public static final Property<String> NAME = new
> Property<String>(NAME_PROPERTY);
> >>> ...
> >>> }
> >>>
> >>> Then client code can do things like:
> >>>
> >>> new SelectQuery(Artist.class, NAME.eq("Pablo").andExp(AGE.gt(40)),
> AGE.descs());
> >>>
> >>> This would select all artists with name equal to Pablo and age greater
> than 40 and order them in descending age order.
> >>>
> >>> This concept has been proven to work incredibly well with WebObjects.
>  It's almost as readable as using plain strings but has complete
> compile-time checking for the property name and the type of the objects it
> is compared with.
> >>>
> >>> A complete implementation is attached.  It's very simple since
> ExpressionFactory does the work.  If this is accepted, it would make sense
> to modify the built-in entity templates to generate Property constants for
> all of the properties.
> >>>
> >>> --
> >>> This message is automatically generated by JIRA.
> >>> If you think it was sent incorrectly, please contact your JIRA
> administrators:
> https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
> >>> For more information on JIRA, see:
> http://www.atlassian.com/software/jira
> >>>
> >>>
> >>>
> >>
> >
>
>

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