All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.hazelcast.org.apache.calcite.plan.RelTraitDef Maven / Gradle / Ivy

There is a newer version: 5.5.0
Show newest version
/*
 * 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.plan;

import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.convert.ConverterRule;

import com.hazelcast.com.google.common.collect.Interner;
import com.hazelcast.com.google.common.collect.Interners;

import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;

/**
 * RelTraitDef represents a class of {@link RelTrait}s. Implementations of
 * RelTraitDef may be singletons under the following conditions:
 *
 * 
    *
  1. if the set of all possible associated RelTraits is finite and fixed (e.g. * all RelTraits for this RelTraitDef are known at compile time). For example, * the CallingConvention trait meets this requirement, because CallingConvention * is effectively an enumeration.
  2. *
  3. Either * *
      *
    • {@link #canConvert(RelOptPlanner, RelTrait, RelTrait)} and * {@link #convert(RelOptPlanner, RelNode, RelTrait, boolean)} do not require * planner-instance-specific information, or
    • * *
    • the RelTraitDef manages separate sets of conversion data internally. See * {@link ConventionTraitDef} for an example of this.
    • *
    *
  4. *
* *

Otherwise, a new instance of RelTraitDef must be constructed and * registered with each new planner instantiated.

* * @param Trait that this trait definition is based upon */ public abstract class RelTraitDef { //~ Instance fields -------------------------------------------------------- /** * Cache of traits. * *

Uses weak interner to allow GC. */ @SuppressWarnings("BetaApi") private final Interner interner = Interners.newWeakInterner(); //~ Constructors ----------------------------------------------------------- protected RelTraitDef() { } //~ Methods ---------------------------------------------------------------- /** * Whether a relational expression may possess more than one instance of * this trait simultaneously. * *

A subset has only one instance of a trait.

*/ public boolean multiple() { return false; } /** Returns the specific RelTrait type associated with this RelTraitDef. */ public abstract Class getTraitClass(); /** Returns a simple name for this RelTraitDef (for use in * {@link com.hazelcast.org.apache.calcite.rel.RelNode#explain}). */ public abstract String getSimpleName(); /** * Takes an arbitrary RelTrait and returns the canonical representation of * that RelTrait. Canonized RelTrait objects may always be compared using * the equality operator (==). * *

If an equal RelTrait has already been canonized and is still in use, * it will be returned. Otherwise, the given RelTrait is made canonical and * returned. * * @param trait a possibly non-canonical RelTrait * @return a canonical RelTrait. */ @SuppressWarnings("BetaApi") public final T canonize(T trait) { if (!(trait instanceof RelCompositeTrait)) { assert getTraitClass().isInstance(trait) : getClass().getName() + " cannot canonize a " + trait.getClass().getName(); } return interner.intern(trait); } /** * Converts the given RelNode to the given RelTrait. * * @param planner the planner requesting the conversion * @param rel RelNode to convert * @param toTrait RelTrait to convert to * @param allowInfiniteCostConverters flag indicating whether infinite cost * converters are allowed * @return a converted RelNode or null if conversion is not possible */ public abstract @Nullable RelNode convert( RelOptPlanner planner, RelNode rel, T toTrait, boolean allowInfiniteCostConverters); /** * Tests whether the given RelTrait can be converted to another RelTrait. * * @param planner the planner requesting the conversion test * @param fromTrait the RelTrait to convert from * @param toTrait the RelTrait to convert to * @return true if fromTrait can be converted to toTrait */ public abstract boolean canConvert( RelOptPlanner planner, T fromTrait, T toTrait); /** * Provides notification of the registration of a particular * {@link ConverterRule} with a {@link RelOptPlanner}. The default * implementation does nothing. * * @param planner the planner registering the rule * @param converterRule the registered converter rule */ public void registerConverterRule( RelOptPlanner planner, ConverterRule converterRule) { } /** * Provides notification that a particular {@link ConverterRule} has been * de-registered from a {@link RelOptPlanner}. The default implementation * does nothing. * * @param planner the planner registering the rule * @param converterRule the registered converter rule */ public void deregisterConverterRule( RelOptPlanner planner, ConverterRule converterRule) { } /** * Returns the default member of this trait. */ public abstract T getDefault(); }





© 2015 - 2024 Weber Informatics LLC | Privacy Policy