-----Original Message----- From: Bruce Snyder [mailto:[EMAIL PROTECTED] Sent: Monday, May 16, 2005 4:52 PM To: [email protected] Subject: Re: [castor-dev] Ordering objects in one-to-many relationship..
>On 5/16/05, Ronald Rudy <[EMAIL PROTECTED]> wrote: >> Can I assume based on the lack of responses that there is no way to sort >> these collections via Castor? >> >> >> -----Original Message----- >> From: Ronald Rudy [mailto:[EMAIL PROTECTED] >> Sent: Monday, May 16, 2005 9:55 AM >> To: [email protected] >> Subject: [castor-dev] Ordering objects in one-to-many relationship.. >> >> I have a simple object that has as an attribute an arraylist of many 'child' >> objects based on a foreign key. This works perfectly fine with the >> following mapping syntax: >> >> <class name="com.xyz.ParentObject" identity="parentId" >> key-generator="SEQUENCE"> >> <description>"Parent Object"</description> >> <map-to table="parent"/> >> <cache-type type="none"/> >> {...} >> <field name="children" type="com.xyz.ChildObject" >> collection="arraylist"> >> <sql many-key="parent_id"/> >> </field> >> {...} >> </class> >> >> This loads perfectly fine without issue, but what I'd like to do is order >> the arraylist that is generated based on two identified columns. Is this >> possible without manually reordering the collected arraylist? > >Ronald, > >Castor does not provide a manner in which to sort the objects in a >collection. The only solution I can I think of is to pass in an ORDER >BY clause in the OQL query. Beyond that maybe we could consider >creating an optional order-by attribute on the field element only for >use with fields of a collection type. > >Bruce >-- >perl -e 'print unpack("u30","D0G)[EMAIL PROTECTED]&5R\"F)R=6-E+G-N>61E<D\!G;6%I;\"YC;VT*" >);' > >The Castor Project >http://www.castor.org/ > >Apache Geronimo >http://geronimo.apache.org/ That would probably be the most logical and efficient way to do it. However, it would also be possible to plug into Java's native 'java.lang.Comparable' based sorting, producing a collection object that implements the java.util.SortedSet interface. This would be datasource independent, though it comes at a processing cost. Supporting both would be possible, and perhaps preferable, to give options. As for now, I'll just use a separate manager object that uses OQL to load and sort the collection manually. -Ron
