It's a bug in how OpAsQuery converts sub-queries, watch this space for a
fix
Rob
On 4/23/13 12:35 PM, "John Liu" <john_ws_...@yahoo.com> wrote:
>oh I see, thanks Rob.
>
>I paste the class here, you will see the exception error when you run the
>code.
> import
>com.hp.hpl.jena.query.Query;import
>com.hp.hpl.jena.query.QueryFactory;import
>com.hp.hpl.jena.sparql.algebra.AlgebraGenerator;import
>com.hp.hpl.jena.sparql.algebra.Op;import
>com.hp.hpl.jena.sparql.algebra.OpAsQuery;public
>classTestJena {
>/***
>@paramargs*/
>publicstaticvoidmain(String[] args) {String queryString =
>"PREFIX dcterms: <http://purl.org/dc/terms/> \n"+
>"PREFIX dbpedia: <http://dbpedia.org/resource/> \n"+
>"SELECT ?num_of_holidays ?celebrate_Chinese_New_Year WHERE { \n"+
>"{"+
>"SELECT ?country_cat (COUNT(?holiday) as ?num_of_holidays) \n"+
>"WHERE {"+
>"?country_cat <http://www.w3.org/2004/02/skos/core#broader>
><http://dbpedia.org/resource/Category:Public_holidays_by_country>. \n"+
>"?holiday dcterms:subject ?country_cat \n"+
>"}GROUP by ?country_cat \n"+
>"} \n"+
>"{ \n"+
>"SELECT ?country_cat (COUNT(?holiday) as ?celebrate_Chinese_New_Year) \n"+
>"WHERE { \n"+
>"?country_cat <http://www.w3.org/2004/02/skos/core#broader>
><http://dbpedia.org/resource/Category:Public_holidays_by_country>. \n"+
>"?holiday dcterms:subject ?country_cat \n"+
>"FILTER(?holiday=\"http://dbpedia.org/resource/Lunar_New_Year\'s_Day\")
>\n"+
>"}GROUP by ?country_cat \n"+
>"} \n"+
>"}\n";System.
>out.println("Original query: \n"+ queryString);Query query =
>QueryFactory.create(queryString);
>AlgebraGenerator ag =
>newAlgebraGenerator();Op op = ag.compile(query);
>Query query2 = OpAsQuery.asQuery(op);
>String queryString2 = query2.toString();
>System.
>out.println("Update query: \n"+ queryString2);Query newQuery2 =
>QueryFactory.create(queryString2);
>}
>}
>
>
>________________________________
> From: Rob Vesse <rve...@yarcdata.com>
>To: "users@jena.apache.org" <users@jena.apache.org>
>Sent: Tuesday, April 23, 2013 2:06:34 PM
>Subject: Re: problem in rewriting query by AlgebraGenerator
>
>
>John
>
>Apache list strips attachments, if you have a code sample please just
>paste it into the email or provide a link to a pastebin/similar site with
>your code sample
>
>Rob
>
>
>On 4/23/13 11:02 AM, "John Liu" <john_ws_...@yahoo.com> wrote:
>
>>Thanks Andy for your quick reply.
>>
>>I tested Jena 2.10.1 and the problem still exists. Could you please run
>>the attached java code to see if it is a defect?
>>
>>Thanks, John
>>
>>
>>________________________________
>> From: Andy Seaborne <a...@apache.org>
>>To: users@jena.apache.org
>>Sent: Tuesday, April 23, 2013 10:46:25 AM
>>Subject: Re: problem in rewriting query by AlgebraGenerator
>>
>>
>>On 23/04/13 03:10, John Liu wrote:
>>> Hello,
>>> I found a problem when rewriting a query by AlgebraGenerator, the
>>> generated query becomes syntax incorrect query. Can you please advise
>>>if
>>> this is a defect? Thanks.
>>> The version of JENA I tested is 2.7.1
>>
>>There have been various improvements and fixes in this area which you'll
>>find in Jena 2.10.0 and in the active development system 2.10.1-SNAPSHOT
>>(from the Apache snapshot maven repository)
>>
>> Andy
>>
>>> The code I rewrite the query is:
>>> Query query = QueryFactory./create/(queryString);
>>> AlgebraGenerator ag =
>>> *new*AlgebraGenerator();
>>> Op op = ag.compile(query);
>>> Query query2 = OpAsQuery./asQuery/(op);
>>> The original query is:
>>> PREFIX dcterms: <http://purl.org/dc/terms/>
>>> PREFIX dbpedia: <http://dbpedia.org/resource/>
>>> SELECT ?num_of_holidays ?celebrate_Chinese_New_Year WHERE {
>>> {SELECT ?country_cat (COUNT(?holiday) as ?num_of_holidays)
>>> WHERE {?country_cat <http://www.w3.org/2004/02/skos/core#broader>
>>> <http://dbpedia.org/resource/Category:Public_holidays_by_country>.
>>> ?holiday dcterms:subject ?country_cat
>>> }GROUP by ?country_cat
>>> }
>>> {
>>> SELECT ?country_cat (COUNT(?holiday) as ?celebrate_Chinese_New_Year)
>>> WHERE {
>>> ?country_cat <http://www.w3.org/2004/02/skos/core#broader>
>>> <http://dbpedia.org/resource/Category:Public_holidays_by_country>.
>>> ?holiday dcterms:subject ?country_cat
>>> FILTER(?holiday="http://dbpedia.org/resource/Lunar_New_Year's_Day")
>>> }GROUP by ?country_cat
>>> }
>>> }
>>> The generated query is:
>>> SELECT ?country_cat ?celebrate_Chinese_New_Year
>>> WHERE
>>> { { ?country_cat <http://www.w3.org/2004/02/skos/core#broader>
>>> <http://dbpedia.org/resource/Category:Public_holidays_by_country> .
>>> ?holiday <http://purl.org/dc/terms/subject> ?country_cat
>>> BIND(count(?holiday) AS ?num_of_holidays)
>>> }
>>> { ?country_cat <http://www.w3.org/2004/02/skos/core#broader>
>>> <http://dbpedia.org/resource/Category:Public_holidays_by_country> .
>>> ?holiday <http://purl.org/dc/terms/subject> ?country_cat
>>> FILTER ( ?holiday = "http://dbpedia.org/resource/Lunar_New_Year's_Day"
>>>)
>>> BIND(count(?holiday) AS ?celebrate_Chinese_New_Year)
>>> }
>>> }
>>> GROUP BY ?country_cat
>>> The generated query has a syntax error: "Line 5, column 12: Aggregate
>>> expression not legal at this point".
>>> Attached is a hava program to demonstrate the problem,
