com.hazelcast.org.apache.calcite.plan.RelOptNode Maven / Gradle / Ivy
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* 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,
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package com.hazelcast.org.apache.calcite.plan;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import java.util.List;
/**
* Node in a planner.
*/
public interface RelOptNode {
/**
* Returns the ID of this relational expression, unique among all relational
* expressions created since the server was started.
*
* @return Unique ID
*/
int getId();
/**
* Returns a string which concisely describes the definition of this
* relational expression. Two relational expressions are equivalent if
* their digests and {@link #getRowType()} (except the field names) are the same.
*
* The digest does not contain the relational expression's identity --
* that would prevent similar relational expressions from ever comparing
* equal -- but does include the identity of children (on the assumption
* that children have already been normalized).
*
*
If you want a descriptive string which contains the identity, call
* {@link Object#toString()}, which always returns "rel#{id}:{digest}".
*
* @return Digest string of this {@code RelNode}
*/
String getDigest();
/**
* Retrieves this RelNode's traits. Note that although the RelTraitSet
* returned is modifiable, it must not be modified during
* optimization. It is legal to modify the traits of a RelNode before or
* after optimization, although doing so could render a tree of RelNodes
* unimplementable. If a RelNode's traits need to be modified during
* optimization, clone the RelNode and change the clone's traits.
*
* @return this RelNode's trait set
*/
RelTraitSet getTraitSet();
// TODO: We don't want to require that nodes have very detailed row type. It
// may not even be known at planning time.
RelDataType getRowType();
/**
* Returns a string which describes the relational expression and, unlike
* {@link #getDigest()}, also includes the identity. Typically returns
* "rel#{id}:{digest}".
*
* @return String which describes the relational expression and, unlike
* {@link #getDigest()}, also includes the identity
*/
@Deprecated // to be removed before 2.0
String getDescription();
/**
* Returns an array of this relational expression's inputs. If there are no
* inputs, returns an empty list, not {@code null}.
*
* @return Array of this relational expression's inputs
*/
List getInputs();
/**
* Returns the cluster this relational expression belongs to.
*
* @return cluster
*/
RelOptCluster getCluster();
}