com.hazelcast.shaded.org.apache.calcite.rel.RelWriter 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.shaded.org.apache.calcite.rel;
import com.hazelcast.shaded.org.apache.calcite.sql.SqlExplainLevel;
import com.hazelcast.shaded.org.apache.calcite.util.Pair;
import com.hazelcast.shaded.org.checkerframework.checker.nullness.qual.Nullable;
import java.util.List;
/**
* Callback for an expression to dump itself to.
*
* It is used for generating EXPLAIN PLAN output, and also for serializing
* a tree of relational expressions to JSON.
*/
public interface RelWriter {
/**
* Prints an explanation of a node, with a list of (term, value) pairs.
*
*
The term-value pairs are generally gathered by calling
* {@link com.hazelcast.shaded.org.apache.calcite.rel.RelNode#explain(RelWriter)}.
* Each sub-class of {@link com.hazelcast.shaded.org.apache.calcite.rel.RelNode}
* calls {@link #input(String, com.hazelcast.shaded.org.apache.calcite.rel.RelNode)}
* and {@link #item(String, Object)} to declare term-value pairs.
*
* @param rel Relational expression
* @param valueList List of term-value pairs
*/
void explain(RelNode rel, List> valueList);
/** Returns detail level at which plan should be generated. */
SqlExplainLevel getDetailLevel();
/**
* Adds an input to the explanation of the current node.
*
* @param term Term for input, e.g. "left" or "input #1".
* @param input Input relational expression
*/
default RelWriter input(String term, RelNode input) {
return item(term, input);
}
/**
* Adds an attribute to the explanation of the current node.
*
* @param term Term for attribute, e.g. "joinType"
* @param value Attribute value
*/
RelWriter item(String term, @Nullable Object value);
/**
* Adds an input to the explanation of the current node, if a condition
* holds.
*/
default RelWriter itemIf(String term, @Nullable Object value, boolean condition) {
return condition ? item(term, value) : this;
}
/**
* Writes the completed explanation.
*/
RelWriter done(RelNode node);
/**
* Returns whether the writer prefers nested values. Traditional explain
* writers prefer flattened values.
*/
default boolean nest() {
return false;
}
}