BTW, I just patched QueryChain to return DataRows all the time and
avoid doing object conversion at all:
http://issues.apache.org/cayenne/browse/CAY-603
Andrus
On Jul 19, 2006, at 6:00 PM, Andrus Adamchik wrote:
Hi Hannes,
Yeah, QueryChain can't handle object conversion, as Cayenne stack
only supports a single metadata object per query. I guess it can at
least use the entity of the first query in a chain, still making it
kind of kludgy. At the very minimum it should return "true" for
"isFetchingDataRows", so that no conversion occurs. I'll work on
fixing this, so thanks for pointing it out.
Still I don't understand why you need to use a chain in your case.
If you want different sets of results for different query values,
just run separate SQLTemplates multiple times. Chain doesn't really
help you here.
Andrus
On Jul 19, 2006, at 7:13 PM, Hannes Janetzek wrote:
Hello,
I have a problem with using the queryChain. I could track down the
error
to the point, that the generic metadata has no data and so
conversion fails. Thats where the null-pointer comes from.
QueryChain query = new QueryChain();
query.addQuery(new SQLTemplate(Bibtex.class, "select * FROM BIBTEX
WHERE "+type[i]+" REGEXP \""+keyword+"\""));
getDataContext().performQuery(query)
The error-stack:
WARN RequestProcessor: Unhandled Exception thrown: class
java.lang.NullPointerException ERROR [action]: Servlet.service() for
servlet action threw exception java.lang.NullPointerException
at
org.objectstyle.cayenne.access.ObjectResolver.init
(ObjectResolver.java:102)
at
org.objectstyle.cayenne.access.ObjectResolver.<init>
(ObjectResolver.java:93)
at
org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjectC
onversion(DataDomainQueryAction.java:373)
at
org.objectstyle.cayenne.access.DataDomainQueryAction.execute
(DataDomainQueryAction.java:151)
at
org.objectstyle.cayenne.access.DataDomain.onQuery(DataDomain.java:
766)
at
org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery
(ObjectContextQueryAction.java:253)
at
org.objectstyle.cayenne.access.DataContextQueryAction.execute
(DataContextQueryAction.java:90)
at
org.objectstyle.cayenne.access.DataContext.onQuery
(DataContext.java:1422)
at
org.objectstyle.cayenne.access.DataContext.performQuery
(DataContext.java:1411)
at dbAccess.DBAccess.findBibtexByRegex(DBAccess.java:95)
On the other hand this works well:
SQLTemplate select = new SQLTemplate(Bibtex.class, "select *
FROM BIBTEX WHERE "+type+" REGEXP \""+keyword+"\"");
getDataContext().performQuery(select);
The problem with this is that if have many items found more than once
that I have to filter out then.
Am I doing somethig wrong or this a known issue?
Regards,
Hannes Janetzek
