com.hazelcast.org.apache.calcite.rel.SingleRel Maven / Gradle / Ivy
/*
* 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.hazelcast.org.apache.calcite.rel;
import com.hazelcast.org.apache.calcite.plan.RelOptCluster;
import com.hazelcast.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.com.google.common.collect.ImmutableList;
import java.util.List;
/**
* Abstract base class for relational expressions with a single input.
*
* It is not required that single-input relational expressions use this
* class as a base class. However, default implementations of methods make life
* easier.
*/
public abstract class SingleRel extends AbstractRelNode {
//~ Instance fields --------------------------------------------------------
protected RelNode input;
//~ Constructors -----------------------------------------------------------
/**
* Creates a SingleRel
.
*
* @param cluster Cluster this relational expression belongs to
* @param input Input relational expression
*/
protected SingleRel(
RelOptCluster cluster,
RelTraitSet traits,
RelNode input) {
super(cluster, traits);
this.input = input;
}
//~ Methods ----------------------------------------------------------------
public RelNode getInput() {
return input;
}
@Override public List getInputs() {
return ImmutableList.of(input);
}
@Override public double estimateRowCount(RelMetadataQuery mq) {
// Not necessarily correct, but a better default than AbstractRelNode's 1.0
return mq.getRowCount(input);
}
@Override public void childrenAccept(RelVisitor visitor) {
visitor.visit(input, 0, this);
}
@Override public RelWriter explainTerms(RelWriter pw) {
return super.explainTerms(pw)
.input("input", getInput());
}
@Override public void replaceInput(
int ordinalInParent,
RelNode rel) {
assert ordinalInParent == 0;
this.input = rel;
recomputeDigest();
}
@Override protected RelDataType deriveRowType() {
return input.getRowType();
}
}