com.hazelcast.org.apache.calcite.rel.core.SortExchange Maven / Gradle / Ivy
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* 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.
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package com.hazelcast.org.apache.calcite.rel.core;
import com.hazelcast.org.apache.calcite.plan.RelOptCluster;
import com.hazelcast.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.org.apache.calcite.rel.RelCollation;
import com.hazelcast.org.apache.calcite.rel.RelCollationTraitDef;
import com.hazelcast.org.apache.calcite.rel.RelDistribution;
import com.hazelcast.org.apache.calcite.rel.RelDistributionTraitDef;
import com.hazelcast.org.apache.calcite.rel.RelInput;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.RelWriter;
import java.util.Objects;
/**
* Relational expression that performs {@link Exchange} and {@link Sort}
* simultaneously.
*
* Whereas a Sort produces output with a particular
* {@link com.hazelcast.org.apache.calcite.rel.RelCollation} and an Exchange produces output
* with a particular {@link com.hazelcast.org.apache.calcite.rel.RelDistribution}, the output
* of a SortExchange has both the required collation and distribution.
*
*
Several implementations of SortExchange are possible; the purpose of this
* base class allows rules to be written that apply to all of those
* implementations.
*/
public abstract class SortExchange extends Exchange {
protected final RelCollation collation;
//~ Constructors -----------------------------------------------------------
/**
* Creates a SortExchange.
*
* @param cluster Cluster this relational expression belongs to
* @param traitSet Trait set
* @param input Input relational expression
* @param distribution Distribution specification
*/
protected SortExchange(RelOptCluster cluster, RelTraitSet traitSet,
RelNode input, RelDistribution distribution, RelCollation collation) {
super(cluster, traitSet, input, distribution);
this.collation = Objects.requireNonNull(collation, "collation");
assert traitSet.containsIfApplicable(collation)
: "traits=" + traitSet + ", collation=" + collation;
}
/**
* Creates a SortExchange by parsing serialized output.
*/
protected SortExchange(RelInput input) {
this(input.getCluster(),
input.getTraitSet().plus(input.getCollation())
.plus(input.getDistribution()),
input.getInput(),
RelDistributionTraitDef.INSTANCE.canonize(input.getDistribution()),
RelCollationTraitDef.INSTANCE.canonize(input.getCollation()));
}
//~ Methods ----------------------------------------------------------------
@Override public final SortExchange copy(RelTraitSet traitSet,
RelNode newInput, RelDistribution newDistribution) {
return copy(traitSet, newInput, newDistribution, collation);
}
public abstract SortExchange copy(RelTraitSet traitSet, RelNode newInput,
RelDistribution newDistribution, RelCollation newCollation);
/**
* Returns the array of {@link com.hazelcast.org.apache.calcite.rel.RelFieldCollation}s
* asked for by the sort specification, from most significant to least
* significant.
*
*
See also
* {@link com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery#collations(RelNode)},
* which lists all known collations. For example,
* ORDER BY time_id might also be sorted by
* the_year, the_month because of a known monotonicity
* constraint among the columns. {@code getCollation} would return
* [time_id] and {@code collations} would return
* [ [time_id], [the_year, the_month] ].
*/
public RelCollation getCollation() {
return collation;
}
@Override public RelWriter explainTerms(RelWriter pw) {
return super.explainTerms(pw)
.item("collation", collation);
}
}