Re: [eclipselink-dev] Key converter support with ElementCollection

["Guy Pelletier" <guy.pelletier@xxxxxxxxxx>]

I like @ConvertKey.

 

Anyone else?

 

Cheers,

Guy

----- Original Message -----

From: Michael Keith

To: guy.pelletier@xxxxxxxxxx ; Dev mailing list for Eclipse Persistence Services

Sent: Wednesday, December 24, 2008 11:18 AM

Subject: RE: [eclipselink-dev] Key converter support with ElementCollection

Yes, good point Guy. There are a few missing cases with map keys in the spec as well (we were not

sure whether it was worth adding the extra complexity to handle what seemed to be less common

case) but we should probably support this in EclipseLink.

 

@Convert would apply to the value of the Map, and perhaps we might introduce a @ConvertKey.

-----Original Message-----
From: Guy Pelletier
Sent: Wednesday, December 24, 2008 10:30 AM
To: Dev mailing list for Eclipse Persistence Services
Subject: [eclipselink-dev] Key converter support with ElementCollection

While working on the ElementCollection support, I noticed there is no way in JPA to specify or support a converter for a key column in a basic map mapping case.

 

Note, JPA doesn't have any explicit support of converters with ElementCollection but we certainly could add some since internally EclipseLink supports them. As it is a @Convert (or a JPA converter, @Lob, @Temporal, @Enumerated) could be applied to the value column of a direct collection or direct map mapping case, but there is no way to specify a converter for the map key.

 

Perhaps we could introduce another annotation? KeyConverter? MapKeyConverter? MapKeyColumnConverter?

 

In the interim, if users wanted a way to have a key converter they could either use EclipseLink's @BasicMap or a customizer to add the converter.

 

Anyway, food for thought over the holidays.

 

Cheers,

Guy