/*
* 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 org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.hp.hpl.jena.sdb.SDB;
import com.hp.hpl.jena.sdb.core.AliasesSql;
import com.hp.hpl.jena.sdb.core.SDBRequest;
import com.hp.hpl.jena.sdb.core.sqlexpr.SqlExprList;
import com.hp.hpl.jena.sdb.core.sqlnode.SqlNode;
import com.hp.hpl.jena.sdb.core.sqlnode.SqlTable;
import com.hp.hpl.jena.sdb.layout2.TableDescQuads;
import com.hp.hpl.jena.sparql.core.Quad;
import com.hp.hpl.jena.sparql.util.FmtUtils;
import org.apache.jena.atlas.io.IndentedWriter;
public class SqlStageBasicQuad implements SqlStage
{
private static Logger log = LoggerFactory.getLogger(SqlStageBasicQuad.class) ;
private Quad quad ;
public SqlStageBasicQuad(Quad quad)
{
this.quad = quad ;
}
// There are three special graph names:
// Quad.defaultGraph - the quad marker for a query pattern for the default graph.
// Quad.defaultGraphName - the explicit internal name for the default graph
// Quad.unionDefaultGraph - the internal name for the union of all named graphs (excluding the degault graph).
//
// If SDB.unionDefaultGraph is true in the context, then patterns on the
// default graph are made against the union graph.
//
// If the explicit names (defaultGraphName, unionDefaultGraph) are used in GRAPH,
// then the default or union beahviour is avilable regardless of the setting of
// SDB.unionDefaultGraph.
@Override
public SqlNode build(SDBRequest request, SlotCompiler slotCompiler)
{
SqlExprList conditions = new SqlExprList() ;
boolean defaultGraph = Quad.isDefaultGraph(quad.getGraph()) ; // ARQ 2.8.4 quad.isDefaultGraph() ;
boolean unionGraph = quad.isUnionGraph() ;
// ---- Choose the mode of access.
boolean accessStoredDefaultGraph = Quad.isDefaultGraph(quad.getGraph()); //quad.isDefaultGraph() ;
boolean accessUnionGraph = false ;
if ( accessStoredDefaultGraph && request.getContext().isTrue(SDB.unionDefaultGraph) )
{
// Treat the default graph as the union of all triples in named graphs.
defaultGraph = false ;
unionGraph = true ;
accessStoredDefaultGraph = false ;
accessUnionGraph = true ;
}
// GRAPH <name of default graph> { }
if ( quad.isDefaultGraphExplicit() )
{
// "named" access to the default graph
accessStoredDefaultGraph = true ;
accessUnionGraph = false ;
}
if ( quad.isUnionGraph() )
{
// "named" access to the union of the named graphs
accessStoredDefaultGraph = false ;
accessUnionGraph = true ;
// Add DISTINCT over the join of SqlStageBasicQuad for RDF merge
}
// ---- Choose the table to access
// The default graph table may be a specialized table (e.g. triples, not quads).
TableDescQuads tableDesc = null ;
String alias = null ;
if ( accessStoredDefaultGraph )
{
tableDesc = request.getStore().getTripleTableDesc() ;
alias = request.genId(AliasesSql.TriplesTableBase) ;
}
else
{
tableDesc = request.getStore().getQuadTableDesc() ;
alias = request.genId(AliasesSql.QuadTableBase) ;
}
SqlTable table = new SqlTable(alias, tableDesc.getTableName()) ;
if ( accessStoredDefaultGraph )
table.addNote(FmtUtils.stringForTriple(quad.asTriple(), request.getPrefixMapping())) ;
else
table.addNote(FmtUtils.stringForQuad(quad, request.getPrefixMapping())) ;
// Only constrain the G column
// IF there is a graph column (so it's not the triples table)
// AND if we are not unioning the named graphs.
if ( ! accessStoredDefaultGraph && ! accessUnionGraph )
slotCompiler.processSlot(request, table, conditions, quad.getGraph(),
tableDesc.getGraphColName()) ;
slotCompiler.processSlot(request, table, conditions, quad.getSubject(),
tableDesc.getSubjectColName()) ;
slotCompiler.processSlot(request, table, conditions, quad.getPredicate(),
tableDesc.getPredicateColName()) ;
slotCompiler.processSlot(request, table, conditions, quad.getObject(),
tableDesc.getObjectColName()) ;
return SqlBuilder.restrict(request, table, conditions) ;
}
@Override
public String toString() { return "Table: "+quad ; }
@Override
public void output(IndentedWriter out)
{ out.print(toString()) ; }
}