/*
* 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.engine.iterator;
import java.util.Iterator ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.sparql.ARQInternalErrorException ;
import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.engine.ExecutionContext ;
import com.hp.hpl.jena.sparql.engine.QueryIterator ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.engine.binding.BindingFactory ;
import com.hp.hpl.jena.sparql.engine.binding.BindingMap ;
import org.apache.jena.atlas.logging.Log ;
/**
* Yield new bindings, with a fixed parent, with values from an iterator.
* Parent must not have variables in common with the iterator stream.
*/
public class QueryIterCommonParent extends QueryIterConvert
{
public QueryIterCommonParent(QueryIterator input, Binding binding, ExecutionContext execCxt)
{
super(input, new ConverterExtend(binding) , execCxt) ;
}
// Extend (with checking) an iterator stream of binding to have a common parent.
static class ConverterExtend implements QueryIterConvert.Converter
{
private Binding parentBinding ;
ConverterExtend(Binding parent) { parentBinding = parent ; }
@Override
public Binding convert(Binding b)
{
if ( parentBinding == null || parentBinding.isEmpty() )
return b ;
// This is the result. Could have BindingBase.setParent etc.
BindingMap b2 = BindingFactory.create(parentBinding) ;
// Copy the resultSet bindings to the combined result binding with checking.
for ( Iterator<Var> iter = b.vars() ; iter.hasNext(); )
{
Var v = iter.next();
Node n = b.get(v) ;
if ( b2.contains(v) )
{
Node n2 = b2.get(v) ;
if ( n2.equals(n) )
Log.warn(this, "Binding already for "+v+" (same value)" ) ;
else
{
Log.fatal(this, "Binding already for "+v+" (different values)" ) ;
throw new ARQInternalErrorException("Incompatible bindings for "+v) ;
}
}
b2.add(v, n) ;
}
return b2 ;
}
}
}