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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.graph;
import java.util.ArrayList ;
import java.util.Iterator ;
import java.util.List ;
import java.util.Objects;
import org.apache.jena.atlas.iterator.Iter ;
import org.apache.jena.graph.Node ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.query.SortCondition ;
import org.apache.jena.sparql.algebra.Op ;
import org.apache.jena.sparql.algebra.Table ;
import org.apache.jena.sparql.algebra.Transform ;
import org.apache.jena.sparql.algebra.Transformer ;
import org.apache.jena.sparql.algebra.table.TableData ;
import org.apache.jena.sparql.core.* ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.engine.binding.BindingFactory ;
import org.apache.jena.sparql.engine.binding.BindingMap ;
import org.apache.jena.sparql.expr.Expr ;
import org.apache.jena.sparql.expr.ExprList ;
public class NodeTransformLib
{
/** Do a node->node conversion of an Op - return original BGP for "no change" */
public static Op transform(NodeTransform nodeTransform, Op op)
{
Transform opTransform = new NodeTransformOp(nodeTransform) ;
return Transformer.transform(opTransform, null, op) ; // No expr transform - we do it ourselves.
}
/** Do a node->node conversion of a BGP - return original BGP for "no change" */
public static BasicPattern transform(NodeTransform nodeTransform, BasicPattern pattern)
{
BasicPattern bgp2 = new BasicPattern() ;
boolean changed = false ;
for ( Triple triple : pattern )
{
Triple t2 = transform(nodeTransform, triple) ;
bgp2.add(t2) ;
if ( t2 != triple )
changed = true ;
}
if ( ! changed )
return pattern ;
return bgp2 ;
}
/** Do a node->node conversion of a QuadPattern - return original QuadPattern for "no change" */
public static QuadPattern transform(NodeTransform nodeTransform, QuadPattern pattern)
{
QuadPattern qp2 = new QuadPattern() ;
boolean changed = false ;
for ( Quad quad : pattern )
{
Quad q2 = transform(nodeTransform, quad) ;
qp2.add(q2) ;
if ( q2 != quad )
changed = true ;
}
if ( ! changed )
return pattern ;
return qp2 ;
}
/** Do a node->node conversion of a Triple - return original Triple for "no change" */
public static Triple transform(NodeTransform nodeTransform, Triple triple)
{
boolean change = false ;
Node s = triple.getSubject() ;
Node p = triple.getPredicate() ;
Node o = triple.getObject() ;
Node s1 = nodeTransform.apply(s) ;
if ( s1 != s ) { change = true ; s = s1 ; }
Node p1 = nodeTransform.apply(p) ;
if ( p1 != p ) { change = true ; p = p1 ; }
Node o1 = nodeTransform.apply(o) ;
if ( o1 != o ) { change = true ; o = o1 ; }
if ( ! change )
return triple ;
return new Triple(s,p,o) ;
}
/** Do a node->node conversion of a Quad - return original Quad for "no change" */
public static Quad transform(NodeTransform nodeTransform, Quad quad)
{
boolean change = false ;
Node s = quad.getSubject() ;
Node p = quad.getPredicate() ;
Node o = quad.getObject() ;
Node g = quad.getGraph() ;
Node g1 = nodeTransform.apply(g) ;
if ( g1 != g ) { change = true ; g = g1 ; }
Node s1 = nodeTransform.apply(s) ;
if ( s1 != s ) { change = true ; s = s1 ; }
Node p1 = nodeTransform.apply(p) ;
if ( p1 != p ) { change = true ; p = p1 ; }
Node o1 = nodeTransform.apply(o) ;
if ( o1 != o ) { change = true ; o = o1 ; }
if ( ! change )
return quad ;
return new Quad(g,s,p,o) ;
}
public static Table transform(Table table, NodeTransform transform) {
// Non-streaming rewrite
List vars = transformVars(transform, table.getVars()) ;
Iterator iter = table.rows() ;
List newRows = new ArrayList<>() ;
for ( ; iter.hasNext() ; ) {
Binding b = iter.next() ;
Binding b2 = transform(b, transform) ;
newRows.add(b2) ;
}
return new TableData(vars, newRows) ;
}
public static Binding transform(Binding b, NodeTransform transform) {
BindingMap b2 = BindingFactory.create() ;
List vars = Iter.toList(b.vars()) ;
for ( Var v : vars ) {
Var v2 = (Var)transform.apply(v) ;
b2.add(v2, b.get(v));
}
return b2 ;
}
/** Do a node->node conversion of a List<Quad> - return original List<Quad> for "no change" */
public static List transformQuads(NodeTransform nodeTransform, List quads)
{
List x = new ArrayList<>() ;
boolean changed = false ;
for ( Quad q : quads )
{
Quad q2 = NodeTransformLib.transform(nodeTransform, q) ;
if ( q != q2 )
changed = true ;
x.add(q2) ;
}
if ( ! changed )
return quads ;
return x ;
}
/** Do a node->node conversion of a VarExprList - return original VarExprList for "no change" */
public static VarExprList transform(NodeTransform nodeTransform, VarExprList varExprList)
{
VarExprList varExprList2 = new VarExprList() ;
boolean changed = false ;
for ( Var v : varExprList.getVars() )
{
Expr expr = varExprList.getExpr(v) ;
Var v2 = (Var)nodeTransform.apply(v) ;
Expr expr2 = ( expr != null ) ? transform(nodeTransform, expr) : null ;
if ( ! Objects.equals(v, v2) || ! Objects.equals(expr, expr2) )
changed = true ;
varExprList2.add(v2, expr2) ;
}
if ( ! changed )
return varExprList ;
return varExprList2 ;
}
public static List transformVars(NodeTransform nodeTransform, List varList)
{
List varList2 = new ArrayList<>(varList.size()) ;
boolean changed = false ;
for ( Var v : varList )
{
Var v2 = (Var)nodeTransform.apply(v) ;
varList2.add(v2) ;
if ( !Objects.equals(v, v2) )
changed = true ;
}
if ( ! changed )
return varList ;
return varList2 ;
}
public static ExprList transform(NodeTransform nodeTransform, ExprList exprList)
{
ExprList exprList2 = new ExprList() ;
boolean changed = false ;
for(Expr expr : exprList)
{
Expr expr2 = transform(nodeTransform, expr) ;
if ( expr != expr2 )
changed = true ;
exprList2.add(expr2) ;
}
if ( ! changed ) return exprList ;
return exprList2 ;
}
public static Expr transform(NodeTransform nodeTransform, Expr expr)
{
return expr.applyNodeTransform(nodeTransform) ;
}
public static List transform(NodeTransform nodeTransform, List conditions)
{
List conditions2 = new ArrayList<>() ;
boolean same = true ;
for ( SortCondition sc : conditions )
{
Expr expr = sc.getExpression() ;
Expr expr2 = transform(nodeTransform, expr) ;
if ( expr != expr2 )
same = false ;
SortCondition sc2 = new SortCondition(expr2, sc.getDirection()) ;
conditions2.add(sc2) ;
}
if ( same )
return conditions ;
return conditions2 ;
}
}
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