/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hp.hpl.jena.sparql.engine.http;
import java.io.InputStream ;
import com.hp.hpl.jena.query.Query ;
import com.hp.hpl.jena.query.QueryExecException ;
import com.hp.hpl.jena.query.ResultSet ;
import com.hp.hpl.jena.query.ResultSetFactory ;
import com.hp.hpl.jena.sparql.algebra.Op ;
import com.hp.hpl.jena.sparql.algebra.OpAsQuery ;
import com.hp.hpl.jena.sparql.algebra.op.OpService ;
import com.hp.hpl.jena.sparql.engine.QueryIterator ;
import com.hp.hpl.jena.sparql.engine.Rename ;
import com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorResultSet ;
import com.hp.hpl.jena.sparql.mgt.Explain ;
import com.hp.hpl.jena.sparql.util.Context ;
/** Execution of OpService */
public class Service
{
public static QueryIterator exec(OpService op, Context context)
{
if ( ! op.getService().isURI() )
throw new QueryExecException("Service URI not bound: "+op.getService()) ;
// This relies on the observation that the query was originally correct,
// so reversing the scope renaming is safe (it merely restores the algebra expression).
// Any variables that reappear should be internal ones that were hidden by renaming
// in the first place.
// Any substitution is also safe because it replaced variables by values.
Op opRemote = Rename.reverseVarRename(op.getSubOp(), true) ;
//Explain.explain("HTTP", opRemote, context) ;
Query query ;
// if ( op.getServiceElement() != null )
// {
// does not cope with substitution?
// query = QueryFactory.make() ;
// query.setQueryPattern(op.getServiceElement().getElement()) ;
// query.setQuerySelectType() ;
// query.setQueryResultStar(true) ;
// }
// else
query = OpAsQuery.asQuery(opRemote) ;
Explain.explain("HTTP", query, context) ;
HttpQuery httpQuery = new HttpQuery(op.getService().getURI()) ;
httpQuery.addParam(HttpParams.pQuery, query.toString() );
httpQuery.setAccept(HttpParams.contentTypeResultsXML) ;
InputStream in = httpQuery.exec() ;
ResultSet rs = ResultSetFactory.fromXML(in) ;
return new QueryIteratorResultSet(rs) ;
}
}