/*
* 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 java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.hp.hpl.jena.graph.Node;
import com.hp.hpl.jena.sdb.core.SDBRequest;
import com.hp.hpl.jena.sdb.core.sqlexpr.SqlColumn;
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.store.TableDesc;
import com.hp.hpl.jena.sparql.core.Quad;
import org.apache.jena.atlas.io.IndentedWriter;
/** A (description of a) table that holds a cached/optimized
* version of a pattern.
*/
public class PatternTable extends TableDesc
{
private static Logger log = LoggerFactory.getLogger(PatternTable.class) ;
static final String subjColName = "subject" ;
// Property => column name
Map <Node, String> cols = new HashMap<Node, String>() ;
public PatternTable(String tableName) { super(tableName) ; }
public void add(Node property, String colname)
{ cols.put(property, colname) ; }
public Map <Node, String> getCols() { return cols ; }
@Override
public boolean hasColumn(String colName)
{ return cols.containsKey(colName) ; }
@Override
public Iterator<String> colNames()
{ return cols.values().iterator() ; }
// trigger if we see a prediate this table supports.
public boolean trigger(Quad quad)
{
for ( Node p : cols.keySet() )
{
if ( p.equals(quad.getPredicate()) )
return true ;
}
return false ;
}
// Start a table from the i'th quad
// Must remove the quad at index i if return is not null.
public SqlStage process(int i, QuadBlock quadBlock)
{
QuadBlock tableQuads = new QuadBlock() ;
Set<Node> predicates = new HashSet<Node>(cols.keySet()) ;
// Use the fact that i'th quad is the trigger
Quad trigger = quadBlock.get(i) ;
Node subject = trigger.getSubject() ;
Node graph = trigger.getGraph() ;
for ( Node p : predicates )
{
int idx = quadBlock.findFirst(i, graph, subject, p, null) ;
if ( idx < 0 )
// No match.
// Conservative - must find all predicates
//return null ;
// Liberal - any predicates
continue ;
Quad q = quadBlock.get(idx) ;
tableQuads.add(q) ;
}
quadBlock.removeAll(tableQuads) ;
SqlStagePatternTable stage = new SqlStagePatternTable(graph, subject, tableQuads) ;
return stage ;
}
class SqlStagePatternTable implements SqlStage
{
private QuadBlock tableQuads ;
private Node graphNode ;
private Node subject ;
public SqlStagePatternTable(Node graphNode, Node subject, QuadBlock tableQuads)
{
this.tableQuads = tableQuads ;
this.subject = subject ;
this.graphNode = graphNode ;
}
@Override
public SqlNode build(SDBRequest request, SlotCompiler slotCompiler)
{
SqlTable sqlTable = new SqlTable("ALIAS", "TABLE") ;
SqlExprList conditions = new SqlExprList() ;
if ( ! Quad.isDefaultGraphGenerated(graphNode) )
log.error("Not the default graph in SqlStagePTable.build") ;
if ( false )
slotCompiler.processSlot(request, sqlTable, conditions, graphNode, subjColName) ;
slotCompiler.processSlot(request, sqlTable, conditions, subject, subjColName) ;
for ( Quad quad : tableQuads )
{
String colName = cols.get(quad.getPredicate()) ;
SqlColumn col = new SqlColumn(sqlTable, colName) ;
Node obj = quad.getObject() ;
slotCompiler.processSlot(request, sqlTable, conditions, obj, colName) ;
}
if ( false )
{
for ( Node pred : cols.keySet() )
{
int idx = tableQuads.findFirst(graphNode, subject, pred, null) ;
if ( idx < 0 )
{
// Liberal
continue ;
//log.error("Can't find quad in SqlStagePTable.build") ;
//throw new SDBException("SqlStagePTable.build") ;
}
Quad q = tableQuads.remove(idx) ;
String colName = cols.get(pred) ;
SqlColumn col = new SqlColumn(sqlTable, colName) ;
Node obj = q.getObject() ;
// if ( Var.isVar(obj) )
// sqlTable.setIdColumnForVar(Var.alloc(obj), col) ;
slotCompiler.processSlot(request, sqlTable, conditions, obj, colName) ;
}
}
return SqlBuilder.restrict(request, sqlTable, conditions) ;
}
@Override
public String toString() { return "PTable"; }
@Override
public void output(IndentedWriter out)
{ out.print("PTable") ; }
}
}