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 <[email protected]>
To: "[email protected]" <[email protected]>
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" <[email protected]> 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 <[email protected]>
>To: [email protected]
>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,
>>
