/*
* 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 org.eigenbase.rel;
import java.util.List;
import org.eigenbase.relopt.*;
/**
* <code>OneRowRel</code> always returns one row, one column (containing the
* value 0).
*/
public final class OneRowRel extends OneRowRelBase {
//~ Constructors -----------------------------------------------------------
/**
* Creates a <code>OneRowRel</code>.
*
* @param cluster {@link RelOptCluster} this relational expression belongs
* to
*/
public OneRowRel(RelOptCluster cluster) {
super(
cluster,
cluster.traitSetOf(Convention.NONE));
}
/**
* Creates a OneRowRel by parsing serialized output.
*/
public OneRowRel(RelInput input) {
super(input.getCluster(), input.getTraitSet());
}
@Override
public RelNode copy(RelTraitSet traitSet, List<RelNode> inputs) {
assert traitSet.containsIfApplicable(Convention.NONE);
assert inputs.isEmpty();
return this;
}
}
// End OneRowRel.java