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From Andrus Adamchik <and...@objectstyle.org>
Subject Re: [jira] [Created] (CAY-1724) Add 'Property' class for easier and better Expression creation
Date Thu, 12 Jul 2012 06:47:22 GMT
I'd still go with the Property... If we have to I'd rather rename reflect.Property to something
else (PropertyDescriptor?), as it is much less exposed to the end users, and it would be great
to keep simple expressive names for the "public" side of the API. 

re: package ... org.apache.cayenne.exp looks like a good place for now. While we are at the
very early stages of 3.2, we'll still have the freedom to move it around later if we decide
this wasn't the right place.

Andrus


On Jul 11, 2012, at 6:08 PM, Robert Zeigler wrote:
> Yes, it will be confusing. :)
> 
> Robert
> 
> On Jul 11, 2012, at 7/119:24 AM , John Huss wrote:
> 
>> Hmm, there is already a Property class in org.apache.cayenne.reflect.
>> Where would this go?  Perhaps org.apache.cayenne.exp
>> or org.apache.cayenne.util?  Will it be confusing to have two classes with
>> the same name?
>> 
>> John
>> 
>> On Wed, Jul 11, 2012 at 2:04 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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