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* Licensed to the Apache Software Foundation (ASF) under one
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* 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.
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package org.apache.jena.sdb.engine;
import org.apache.jena.query.ARQ ;
import org.apache.jena.query.Query ;
import org.apache.jena.sdb.SDB ;
import org.apache.jena.sdb.SDBException ;
import org.apache.jena.sdb.Store ;
import org.apache.jena.sdb.compiler.OpSQL ;
import org.apache.jena.sdb.compiler.SDBCompile ;
import org.apache.jena.sdb.core.SDBRequest ;
import org.apache.jena.sdb.store.DatasetGraphSDB ;
import org.apache.jena.sparql.ARQConstants ;
import org.apache.jena.sparql.algebra.Algebra ;
import org.apache.jena.sparql.algebra.Op ;
import org.apache.jena.sparql.algebra.Transformer ;
import org.apache.jena.sparql.algebra.optimize.TransformFilterEquality ;
import org.apache.jena.sparql.algebra.optimize.TransformPropertyFunction ;
import org.apache.jena.sparql.core.DatasetGraph ;
import org.apache.jena.sparql.engine.* ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.engine.binding.BindingRoot ;
import org.apache.jena.sparql.engine.iterator.QueryIterRoot ;
import org.apache.jena.sparql.engine.iterator.QueryIterSingleton ;
import org.apache.jena.sparql.engine.iterator.QueryIteratorCheck ;
import org.apache.jena.sparql.engine.main.QC ;
import org.apache.jena.sparql.util.Context ;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class QueryEngineSDB extends QueryEngineBase
{
private static Logger log = LoggerFactory.getLogger(QueryEngineSDB.class) ;
private Store store ;
private SDBRequest request = null ;
private Op originalOp = null ;
public QueryEngineSDB(Store store, Query q)
{
this(new DatasetGraphSDB(store, SDB.getContext().copy()), q, BindingRoot.create(), SDB.getContext().copy()) ;
}
public QueryEngineSDB(DatasetGraphSDB dsg, Query query, Binding initialBinding, Context context)
{
super(query, dsg, initialBinding, context) ;
init(dsg, query, initialBinding, context) ;
}
public QueryEngineSDB(DatasetGraphSDB dsg, Op op, Binding initialBinding, Context context)
{
super(op, dsg, initialBinding, context) ;
init(dsg, null, initialBinding, context) ;
}
// @Override
// protected Op modifyOp(Op op)
// {
// return op ;
// }
private void init(DatasetGraphSDB dsg, Query query, Binding initialBinding, Context context)
{
if ( context == null )
context = ARQ.getContext().copy() ;
// See "DynamicDatasets" -- this could be enabled.
if ( query != null )
{
if ( query.hasDatasetDescription() )
throw new SDBException("Queries with dataset descriptions (FROM/FROM NAMED) not supported" ) ;
}
if ( context.isDefined(ARQConstants.sysDatasetDescription) )
throw new SDBException("Queries with dataset descriptions set in the context not supported" ) ;
this.store = dsg.getStore() ;
this.request = new SDBRequest(store, query, context) ;
this.originalOp = getOp() ;
// Enable transformations : use own choice of transformations.
// e.g. don't place filters
// Op op = Algebra.optimize(originalOp, context) ;
Op op = originalOp ;
// Do property functions.
op = Transformer.transform(new TransformPropertyFunction(context), op) ;
op = Transformer.transform(new TransformFilterEquality(), op) ;
// Quad it now so it can be passed to Compile.compile
op = Algebra.toQuadForm(op) ;
// Compile to SQL / extract parts to execute as SQL.
op = SDBCompile.compile(store, op, initialBinding, context, request) ;
setOp(op) ;
}
public SDBRequest getRequest() { return request ; }
@Override
public void close()
{
super.close();
}
@Override
public QueryIterator eval(Op op, DatasetGraph dsg, Binding binding, Context context)
{
ExecutionContext execCxt = new ExecutionContext(context, dsg.getDefaultGraph(), dsg, QC.getFactory(context)) ;
// This pattern is common to QueryEngineMain - find a sharing pattern
if ( ! ( op instanceof OpSQL ) )
{
// Not top - invoke the main query engine as a framework to
// put all the sub-opSQL parts together.
QueryIterator input = QueryIterSingleton.create(binding, execCxt) ;
QueryIterator qIter = QC.execute(op, input, execCxt) ; // OpExecutor from main query engine.
qIter = QueryIteratorCheck.check(qIter, execCxt) ;
return qIter ;
}
// Direct.
OpSQL opSQL = (OpSQL)op ;
QueryIterator qIter ;
if ( opSQL.getSqlNode() == null )
{
// Empty BGP, nothing else.
// Just return the answer.
if ( binding != null && binding.size() != 0 )
qIter = QueryIterSingleton.create(binding, execCxt) ;
else
qIter = QueryIterRoot.create(execCxt) ;
}
else
qIter = opSQL.exec(binding, execCxt) ;
qIter = QueryIteratorCheck.check(qIter, execCxt) ;
return qIter ;
}
// -------- Factory
static private QueryEngineFactory factory = new QueryEngineFactorySDB() ;
static public QueryEngineFactory getFactory() { return factory ; }
static public void register() { QueryEngineRegistry.addFactory(factory) ; }
static public void unregister() { QueryEngineRegistry.removeFactory(factory) ; }
private static class QueryEngineFactorySDB implements QueryEngineFactory
{
@Override
public boolean accept(Query query, DatasetGraph dataset, Context context)
{
if ( dataset instanceof DatasetGraphSDB )
return true ;
return false ;
}
@Override
public Plan create(Query query, DatasetGraph dataset, Binding inputBinding, Context context)
{
QueryEngineSDB qe = new QueryEngineSDB((DatasetGraphSDB)dataset , query, inputBinding, context) ;
return qe.getPlan() ;
}
@Override
public boolean accept(Op op, DatasetGraph dataset, Context context)
{
if ( dataset instanceof DatasetGraphSDB )
return true ;
return false ;
}
@Override
public Plan create(Op op, DatasetGraph dataset, Binding inputBinding, Context context)
{
if ( inputBinding == null )
inputBinding = BindingRoot.create();
QueryEngineSDB qe = new QueryEngineSDB((DatasetGraphSDB)dataset, op, inputBinding, context) ;
return qe.getPlan() ;
}
}
}