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Posted to user@cayenne.apache.org by "Alexander Lamb (dev)" <al...@mac.com> on 2007/12/10 17:53:54 UTC

More than one ordering for in memory sort

Hello List,

I am sorting a to-many list in memory:

     List<RegistryEnrollment> re = getEnrollments();
     Ordering ordering = new Ordering("year", true);
     ordering.orderList(re);
     return re;

But I would like to add a second sort criteria (month after year)

I found there were expressions, but no example for formatting them.

Thanks,

Alex

--
Alexander Lamb
alamb@mac.com

Re: More than one ordering for in memory sort

Posted by Kevin Menard <km...@servprise.com>.
On 12/10/07 12:31 PM, "Andrus Adamchik" <an...@objectstyle.org> wrote:

> You should use a static Ordering method that takes a list of orderings:
> 
>      Ordering.orderList(List<?> objects, List<Comparator<Object>>
> orderings)
> 
> Andrus

Ahh, yes.  I forgot about that one.  I was actually just playing with it
last week.

-- 
Kevin

Re: More than one ordering for in memory sort

Posted by Andrus Adamchik <an...@objectstyle.org>.
You should use a static Ordering method that takes a list of orderings:

     Ordering.orderList(List<?> objects, List<Comparator<Object>>  
orderings)

Andrus




On Dec 10, 2007, at 7:21 PM, Kevin Menard wrote:

> I'm not sure how you'd go about it this way, but you can add any  
> number of
> Orderings to a SelectQuery.  If the objects are already cached, you
> shouldn't really see a performance hit.  I've not tried it myself,  
> however.
>
> -- 
> Kevin
>
> On 12/10/07 11:53 AM, "Alexander Lamb (dev)" <al...@mac.com> wrote:
>
>> Hello List,
>>
>> I am sorting a to-many list in memory:
>>
>>     List<RegistryEnrollment> re = getEnrollments();
>>     Ordering ordering = new Ordering("year", true);
>>     ordering.orderList(re);
>>     return re;
>>
>> But I would like to add a second sort criteria (month after year)
>>
>> I found there were expressions, but no example for formatting them.
>>
>> Thanks,
>>
>> Alex
>>
>> --
>> Alexander Lamb
>> alamb@mac.com
>
>

Re: More than one ordering for in memory sort

Posted by Kevin Menard <km...@servprise.com>.
I'm not sure how you'd go about it this way, but you can add any number of
Orderings to a SelectQuery.  If the objects are already cached, you
shouldn't really see a performance hit.  I've not tried it myself, however.

-- 
Kevin

On 12/10/07 11:53 AM, "Alexander Lamb (dev)" <al...@mac.com> wrote:

> Hello List,
> 
> I am sorting a to-many list in memory:
> 
>      List<RegistryEnrollment> re = getEnrollments();
>      Ordering ordering = new Ordering("year", true);
>      ordering.orderList(re);
>      return re;
> 
> But I would like to add a second sort criteria (month after year)
> 
> I found there were expressions, but no example for formatting them.
> 
> Thanks,
> 
> Alex
> 
> --
> Alexander Lamb
> alamb@mac.com