/*
* 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.algebra.op;
import java.util.ArrayList ;
import java.util.List ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.graph.Triple ;
import com.hp.hpl.jena.sparql.algebra.Op ;
import com.hp.hpl.jena.sparql.algebra.OpVisitor ;
import com.hp.hpl.jena.sparql.algebra.Transform ;
import com.hp.hpl.jena.sparql.core.BasicPattern ;
import com.hp.hpl.jena.sparql.core.Quad ;
import com.hp.hpl.jena.sparql.core.QuadPattern ;
import com.hp.hpl.jena.sparql.sse.Tags ;
import com.hp.hpl.jena.sparql.util.NodeIsomorphismMap ;
/** A list of quads.
*
* <code>OpQuadBlock</code> is anny colelction of quads, whereas
* {@linkplain OpQuadPattern} is quads with the same graph node.
* The flip in naming is historical.
*/
public class OpQuadBlock extends Op0
{
public static boolean isQuadBlock(Op op)
{
return (op instanceof OpQuadBlock ) ;
}
private final QuadPattern quads ;
// A QuadPattern is a block of quads with the same graph arg.
// i.e. a BasicGraphPattern. This gets the blank node scoping right.
// Quads are for a specific quad store.
// Later, we may introduce OpQuadBlock for this and OpQuadPattern becomes
// a sequence of such blocks.
public static OpQuadBlock create(Node quadNode, BasicPattern triples) {
QuadPattern qp = new QuadPattern() ;
for ( Triple t : triples ) {
qp.add(new Quad(quadNode, t)) ;
}
return new OpQuadBlock(qp) ;
}
public OpQuadBlock() { quads = new QuadPattern() ; }
public OpQuadBlock(QuadPattern quads) { this.quads = quads ; }
public OpQuadBlock(OpQuadPattern quadPattern) { this.quads = quadPattern.getPattern() ; }
public QuadPattern getPattern() {
return quads ;
}
public boolean isEmpty() { return quads.size() == 0 ; }
@Override
public String getName() { return Tags.tagQuadBlock ; }
@Override
public Op apply(Transform transform) { return transform.transform(this) ; }
@Override
public void visit(OpVisitor opVisitor) { opVisitor.visit(this) ; }
@Override
public Op0 copy() { return new OpQuadBlock(quads) ; }
public List<OpQuadPattern> convert() {
List<OpQuadPattern> x = new ArrayList<OpQuadPattern>() ;
Node gn = null ;
BasicPattern bgp = null ;
for ( Quad q : quads ) {
if ( gn == null || ! gn.equals(q.getGraph()) ) {
if ( gn != null )
x.add(new OpQuadPattern(gn, bgp)) ;
gn = q.getGraph() ;
bgp = new BasicPattern() ;
}
bgp.add(q.asTriple());
}
x.add(new OpQuadPattern(gn, bgp)) ;
return x ;
}
/** Convenience - convert to OpQuadPatterns which are more widely used (currently?) */
public Op convertOp() {
if ( quads.size() == 0 )
return OpTable.empty() ;
if ( quads.size() == 1 )
{
Quad q = quads.get(0) ;
BasicPattern bgp = new BasicPattern() ;
bgp.add(q.asTriple()) ;
return new OpQuadPattern(q.getGraph(), bgp) ;
}
List<OpQuadPattern> x = convert() ;
OpSequence ops = OpSequence.create() ;
for ( OpQuadPattern oqp : x )
ops.add(oqp);
return ops ;
}
@Override
public int hashCode()
{
int calcHashCode = OpBase.HashBasicGraphPattern ;
calcHashCode ^= quads.hashCode() ;
return calcHashCode ;
}
@Override
public boolean equalTo(Op other, NodeIsomorphismMap labelMap)
{
if ( ! ( other instanceof OpQuadBlock ) ) return false ;
OpQuadBlock opQuad = (OpQuadBlock)other ;
return quads.equiv(opQuad.quads, labelMap) ;
}
}