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ARQ is a SPARQL 1.1 query engine for Apache Jena
/*
* 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 org.apache.jena.sparql.resultset;
import java.util.* ;
import org.apache.jena.atlas.iterator.Iter ;
import org.apache.jena.graph.Node ;
import org.apache.jena.query.* ;
import org.apache.jena.rdf.model.Model ;
import org.apache.jena.sparql.core.Var ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.engine.binding.BindingUtils ;
import org.apache.jena.sparql.util.NodeIsomorphismMap ;
import org.apache.jena.sparql.util.NodeUtils ;
import org.apache.jena.sparql.util.NodeUtils.EqualityTest ;
/** Comparison of ResultSets.
* Note that reading ResultSets is destructive so consider using {@link ResultSetRewindable}
* from {@link ResultSetFactory#makeRewindable}
*/
public class ResultSetCompare
{
// Need to extend then use Iso/IsoMatcher to do result sets.
// That needs backtracking.
/* This is from the DAWG test suite.
* Result set 1:
* ---------------
* | x | y |
* ===============
* | _:b0 | _:b1 |
* | _:b2 | _:b3 |
* | _:b1 | _:b0 |
* ---------------
* Result set 2:
* ---------------
* | x | y |
* ===============
* | _:b1 | _:b0 |
* | _:b3 | _:b2 |
* | _:b2 | _:b3 |
* ---------------
*/
// private static String[] rs1$ = {
// "(resultset (?x ?y)",
// " (row (?x _:b0) (?y _:b1))",
// " (row (?x _:b2) (?y _:b3))",
// " (row (?x _:b1) (?y _:b0))",
// ")"} ;
// private static String[] rs2$ = {
// "(resultset (?x ?y)",
// " (row (?x _:c1) (?y _:c0))",
// " (row (?x _:c3) (?y _:c2))",
// " (row (?x _:c2) (?y _:c3))",
// ")"} ;
//
// Limitations:
// This code does not do compare/isomorphism combined with value testing.
// It drops to graph isomorphism, which is term based.
/** Compare two result sets for equivalence. Equivalence means:
* A row rs1 has one matching row in rs2, and vice versa.
* A row is only matched once.
* Rows match if they have the same variables with the same values.
* bNodes must map to a consistent other bNodes. Value comparisons of nodes.
*
* Destructive - rs1 and rs2 are both read, possibly to exhaustion.
* @param rs1
* @param rs2
* @return true if they are equivalent
*/
public static boolean equalsByValue(ResultSet rs1, ResultSet rs2) {
if ( ! compareHeader(rs1, rs2) ) return false ;
//return equivalent(convert(rs1), convert(rs2), new BNodeIso(NodeUtils.sameValue)) ;
ResultSetRewindable rs1a = ResultSetFactory.makeRewindable(rs1) ;
ResultSetRewindable rs2a = ResultSetFactory.makeRewindable(rs2) ;
if ( equivalent(convert(rs1a), convert(rs2a), new BNodeIso(NodeUtils.sameValue)) )
return true ;
rs1a.reset() ;
rs2a.reset() ;
return isomorphic(rs1a, rs2a) ;
}
public static boolean equalsByTest(Collection b1, Collection b2, EqualityTest match)
{
List rows1 = new ArrayList<>(b1);
List rows2 = new ArrayList<>(b2);
return equivalent(rows1, rows2, match);
}
/** compare two result sets for equivalence. Equivalence means:
* A row rs1 has one matching row in rs2, and vice versa.
* A row is only matched once.
* Rows match if they have the same variables with the same values,
* bNodes must map to a consistent other bNodes.
* Term comparisons of nodes.
*
* Destructive - rs1 and rs2 are both read, possibly to exhaustion.
* @param rs1
* @param rs2
* @return true if they are equivalent
*/
public static boolean equalsByTerm(ResultSet rs1, ResultSet rs2) {
if ( ! compareHeader(rs1, rs2) ) return false ;
//return equivalent(convert(rs1), convert(rs2), new BNodeIso(NodeUtils.sameTerm)) ;
ResultSetRewindable rs1a = ResultSetFactory.makeRewindable(rs1) ;
ResultSetRewindable rs2a = ResultSetFactory.makeRewindable(rs2) ;
// Aligned rows
if ( equivalent(convert(rs1a), convert(rs2a), new BNodeIso(NodeUtils.sameTerm)) )
return true ;
rs1a.reset() ;
rs2a.reset() ;
return isomorphic(rs1a, rs2a) ;
}
/** Compare two result sets for equivalence. Equivalence means:
* Each row in rs1 matches the same index row in rs2.
* Rows match if they have the same variables with the same values,
* bNodes must map to a consistent other bNodes.
* Value comparisons of nodes.
*
* Destructive - rs1 and rs2 are both read, possibly to exhaustion.
* @param rs1
* @param rs2
* @return true if they are equivalent
*/
public static boolean equalsByValueAndOrder(ResultSet rs1, ResultSet rs2) {
if ( ! compareHeader(rs1, rs2) )
return false ;
return equivalentByOrder(convert(rs1) , convert(rs2), new BNodeIso(NodeUtils.sameValue)) ;
}
/** compare two result sets for equivalence. Equivalence means:
* Each row in rs1 matchs the same index row in rs2.
* Rows match if they have the same variables with the same values,
* bNodes must map to a consistent other bNodes.
* RDF term comparisons of nodes.
*
* Destructive - rs1 and rs2 are both read, possibly to exhaustion.
* @param rs1
* @param rs2
* @return true if they are equivalent
*/
public static boolean equalsByTermAndOrder(ResultSet rs1, ResultSet rs2) {
if ( ! compareHeader(rs1, rs2) ) return false ;
return equivalentByOrder(convert(rs1) , convert(rs2), new BNodeIso(NodeUtils.sameTerm)) ;
}
/** compare two result sets for exact equality equivalence.
* Exact equalitymeans:
* Each row in rs1 matches the same index row in rs2.
* Rows match if they have the same variables with the same values,
* bNodes must have same labels
*
* Destructive - rs1 and rs2 are both read, possibly to exhaustion.
* @param rs1
* @param rs2
* @return true if they are equivalent
*/
public static boolean equalsExact(ResultSet rs1, ResultSet rs2)
{
if ( ! compareHeader(rs1, rs2) ) return false ;
return equivalentByOrder(convert(rs1) , convert(rs2), new EqualityTest(){}) ;
}
/** Compare two result sets for bNode isomorphism equivalence.
* Only does RDF term comparison.
*/
public static boolean isomorphic(ResultSet rs1, ResultSet rs2) {
Model m1 = RDFOutput.encodeAsModel(rs1) ;
Model m2 = RDFOutput.encodeAsModel(rs2) ;
return m1.isIsomorphicWith(m2) ;
}
/** Compare two bindings, use the node equality test provided */
static public boolean equal(Binding bind1, Binding bind2, NodeUtils.EqualityTest test) {
if ( bind1 == bind2 )
return true ;
if ( bind1.size() != bind2.size() )
return false ;
// They are the same size so containment is enough.
if ( ! containedIn(bind1, bind2, test) ) return false ;
return true ;
}
static private boolean compareHeader(ResultSet rs1, ResultSet rs2) {
if ( rs1 == null && rs2 == null )
return true ;
if ( rs1 == null )
return false ;
if ( rs2 == null )
return false ;
Set names1 = new HashSet<>(rs1.getResultVars()) ;
Set names2 = new HashSet<>(rs2.getResultVars()) ;
return names1.equals(names2) ;
}
static private List convert(ResultSet rs) {
return Iter.iter(rs).map(item -> BindingUtils.asBinding(item)).toList() ;
}
// static boolean equivalentByTerm(ResultSet rs1, ResultSet rs2)
// {
// return equivalent(convert(rs1), convert(rs2), sameTerm) ;
// }
static private boolean equivalent(Collection rows1, Collection rows2, EqualityTest match) {
if ( rows1.size() != rows2.size() )
return false ;
for ( Binding row1 : rows1 ) {
// find in rows2.
Binding matched = null ;
for ( Binding row2 : rows2 ) {
// NEED BACKTRACKING
if ( equal(row1, row2, match) ) {
matched = row2 ;
break ;
}
}
if ( matched == null )
return false ;
// Remove matching.
rows2.remove(matched) ;
}
return true ;
}
static private boolean equivalentByOrder(List rows1, List rows2, EqualityTest match) {
if ( rows1.size() != rows2.size() )
return false ;
Iterator iter1 = rows1.iterator() ;
Iterator iter2 = rows2.iterator() ;
while ( iter1.hasNext() )
{
// Does not need backtracking because rows must
// align and so must variables in a row.
Binding row1 = iter1.next() ;
Binding row2 = iter2.next() ;
if ( !equal(row1, row2, match) )
return false ;
}
return true ;
}
// Is bind1 contained in bind2? For every (var,value) in bind1, is it in bind2?
// Maybe more in bind2.
private static boolean containedIn(Binding bind1, Binding bind2, EqualityTest test) {
// There are about 100 ways to do this!
Iterator iter1 = bind1.vars() ;
while(iter1.hasNext()) {
Var v = iter1.next() ;
Node n1 = bind1.get(v) ;
Node n2 = bind2.get(v) ;
if ( n2 == null )
// v bound in bind1 and not in bind2.
return false ;
if ( ! test.equal(n1, n2) )
return false ;
}
return true ;
}
public static class BNodeIso implements EqualityTest
{
private NodeIsomorphismMap mapping ;
private EqualityTest literalTest ;
public BNodeIso(EqualityTest literalTest) {
this.mapping = new NodeIsomorphismMap() ;
this.literalTest = literalTest ;
}
@Override
public boolean equal(Node n1, Node n2) {
if ( n1 == null && n2 == null )
return true ;
if ( n1 == null )
return false ;
if ( n2 == null )
return false ;
if ( n1.isURI() && n2.isURI() )
return n1.equals(n2) ;
if ( n1.isLiteral() && n2.isLiteral() )
return literalTest.equal(n1, n2) ;
if ( n1.isBlank() && n2.isBlank() )
return mapping.makeIsomorphic(n1, n2) ;
return false ;
}
}
}