/*
* Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
*
* Project and contact information: http://www.cascading.org/
*
* This file is part of the Cascading project.
*
* Licensed 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 cascading.lingual.optiq;
import java.util.Collections;
import org.eigenbase.rel.CalcRel;
import org.eigenbase.rel.RelCollation;
import org.eigenbase.rel.RelNode;
import org.eigenbase.rel.convert.ConverterRule;
import org.eigenbase.relopt.Convention;
import org.eigenbase.rex.RexMultisetUtil;
/**
*
*/
class CascadingCalcConverterRule extends ConverterRule
{
public static final CascadingCalcConverterRule INSTANCE = new CascadingCalcConverterRule();
public CascadingCalcConverterRule()
{
super( CalcRel.class, Convention.NONE, Cascading.CONVENTION, "CascadingCalcConverterRule" );
}
@Override
public RelNode convert( RelNode rel )
{
// stolen from JavaRules.EnumerableAggregateRule
final CalcRel calc = (CalcRel) rel;
final RelNode convertedChild = convert( calc.getChild(), calc.getTraitSet().replace( Cascading.CONVENTION ) );
if( convertedChild == null )
return null; // We can't convert the child, so we can't convert rel.
// If there's a multiset, let FarragoMultisetSplitter work on it
// first.
if( RexMultisetUtil.containsMultiset( calc.getProgram() ) )
return null;
return new CascadingCalcRel( rel.getCluster(), rel.getTraitSet(), convertedChild, rel.getRowType(), calc.getProgram(), Collections.<RelCollation>emptyList() );
}
}