/*
* 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.util;
import java.util.ArrayList ;
import java.util.List ;
import com.hp.hpl.jena.query.QuerySolution ;
import com.hp.hpl.jena.query.ResultSet ;
import com.hp.hpl.jena.rdf.model.Literal ;
import com.hp.hpl.jena.rdf.model.RDFNode ;
import com.hp.hpl.jena.rdf.model.Resource ;
import com.hp.hpl.jena.sparql.ARQException ;
import com.hp.hpl.jena.sparql.resultset.ResultSetMem ;
public class ResultSetUtils
{
/**
* Extracts a List filled with the binding of selectElement variable for each
* query solution as RDFNodes (Resources or Literals).
* Exhausts the result set. Create a rewindable one to use multiple times.
*
* @see com.hp.hpl.jena.query.ResultSetFactory
*/
public static List<RDFNode> resultSetToList(ResultSet rs, String selectElement)
{
// feature suggested by James Howison
List<RDFNode> items = new ArrayList<>() ;
while (rs.hasNext())
{
QuerySolution qs = rs.nextSolution() ;
RDFNode n = qs.get(selectElement) ;
items.add(n) ;
}
return items ;
}
/**
* Extracts a List filled with the binding of selectElement variable for each
* query solution, turned into a string (URIs or lexical forms).
* Exhausts the result set. Create a rewindable one to use multiple times.
* @see com.hp.hpl.jena.query.ResultSetFactory
*/
public static List<String> resultSetToStringList(ResultSet rs,
String selectElement,
String literalOrResource)
{
// feature suggested by James Howison
List<String> items = new ArrayList<>() ;
while (rs.hasNext())
{
QuerySolution qs = rs.nextSolution() ;
RDFNode rn = qs.get(selectElement) ;
if ( rn.isLiteral() )
items.add( ((Literal)rn).getLexicalForm() ) ;
else if ( rn.isURIResource() )
items.add( ((Resource)rn).getURI() ) ;
else if ( rn.isAnon() )
{
items.add( ((Resource)rn).getId().getLabelString() ) ;
}
else
throw new ARQException("Unknow thing in results : "+rn) ;
}
return items ;
}
/**
* Create an in-memory result set from an array of
* ResulSets. It is assumed that all the ResultSets
* from the array have the same variables.
*
* @param sets the ResultSets to concatenate.
*/
public static ResultSet union(ResultSet... sets) {
return new ResultSetMem(sets);
}
}