/*
* 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.sdb.compiler;
import com.hp.hpl.jena.sparql.core.Quad;
import com.hp.hpl.jena.sdb.SDB;
import com.hp.hpl.jena.sdb.core.SDBRequest;
import com.hp.hpl.jena.sdb.core.sqlnode.SqlNode;
import com.hp.hpl.jena.sdb.shared.SDBInternalError;
public class QuadBlockCompilerMain implements QuadBlockCompiler
{
SDBRequest request ;
SlotCompiler slotCompiler ;
static public PatternTable patternTable = null ;
public QuadBlockCompilerMain(SDBRequest request, SlotCompiler slotCompiler)
{
//super(request, slotCompiler) ;
this.request = request ;
this.slotCompiler = slotCompiler ;
}
@Override
public SlotCompiler getSlotCompiler()
{ return slotCompiler ; }
//@Override
@Override
final
public SqlNode compile(QuadBlock quads)
{
SqlNode sqlNode = slotCompiler.start(quads) ;
quads = new QuadBlock(quads) ; // Copy it because it's modified.
// ---- Stage builder
SqlStageList sList = new SqlStageList() ;
// Potential concurrent modification - need to use an explicit index.
for ( int i = 0 ; i < quads.size() ; )
{
Quad q = quads.get(i) ;
if ( patternTable != null && patternTable.trigger(q) )
{
// Removes current quad
SqlStage stage = patternTable.process(i, quads) ;
if ( stage != null )
{
if ( quads.get(i) == q )
throw new SDBInternalError("Pattern table returned a stage but did not remove the first quad") ;
sList.add(stage) ;
continue ;
}
}
sList.add(new SqlStageBasicQuad(q)) ;
i++ ;
}
// ---- and now turn the stages into SqlNodes
SqlNode sqlStages = sList.build(request, slotCompiler) ;
// --- Join the initial node (constants).
sqlNode = SqlBuilder.innerJoin(request, sqlNode, sqlStages) ;
sqlNode = slotCompiler.finish(sqlNode, quads) ;
// Insert DISTINCT if accessing the RDF merge of all named graphs
// An RDF Merge is the DISTINCT results of query over the union of all graphs.
// Or in TransformSDB
boolean needDistinct = false ;
// Either it's the uniongraph ...
if ( quads.getGraphNode().equals(Quad.unionGraph) )
needDistinct = true ;
// Or it's the union graph via redirected defaultGraph
else if ( Quad.isDefaultGraphGenerated(quads.getGraphNode()) &&
request.getContext().isTrue(SDB.unionDefaultGraph))
needDistinct = true ;
if ( needDistinct )
{
// DISTINCT -- over the named variables but not * (which includes the graph node).
String renameName = request.genId("A") ;
//sqlNode = SqlRename.view(renameName, sqlNode) ;
sqlNode = SqlBuilder.view(request, sqlNode) ;
sqlNode = SqlBuilder.distinct(request, sqlNode) ;
}
return sqlNode ;
}
}