org.apache.calcite.plan

Class ConventionTraitDef

java.lang.Object

org.apache.calcite.plan.RelTraitDef<Convention>

org.apache.calcite.plan.ConventionTraitDef

public class ConventionTraitDef
extends RelTraitDef<Convention>

Definition of the the convention trait. A new set of conversion information is created for each planner that registers at least one ConverterRule instance.

Conversion data is held in a LoadingCache with weak keys so that the JVM's garbage collector may reclaim the conversion data after the planner itself has been garbage collected. The conversion information consists of a graph of conversions (from one calling convention to another) and a map of graph arcs to ConverterRules.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ConventionTraitDef.ConversionData Workspace for converting from one convention to another.

Field Summary

Fields

Modifier and Type	Field and Description
private com.google.common.cache.LoadingCache<RelOptPlanner,ConventionTraitDef.ConversionData>	conversionCache Weak-key cache of RelOptPlanner to ConversionData.
static ConventionTraitDef	INSTANCE

Constructor Summary

Constructors

Modifier	Constructor and Description
private	ConventionTraitDef()

Method Summary

Modifier and Type	Method and Description
boolean	canConvert(RelOptPlanner planner, Convention fromConvention, Convention toConvention) Tests whether the given RelTrait can be converted to another RelTrait.
private RelNode	changeConvention(RelNode rel, Convention source, Convention target, com.google.common.collect.Multimap<Pair<Convention,Convention>,ConverterRule> mapArcToConverterRule) Tries to convert a relational expression to the target convention of an arc.
RelNode	convert(RelOptPlanner planner, RelNode rel, Convention toConvention, boolean allowInfiniteCostConverters) Converts the given RelNode to the given RelTrait.
void	deregisterConverterRule(RelOptPlanner planner, ConverterRule converterRule) Provides notification that a particular ConverterRule has been de-registered from a RelOptPlanner.
private ConventionTraitDef.ConversionData	getConversionData(RelOptPlanner planner)
Convention	getDefault() Returns the default member of this trait.
String	getSimpleName()
Class<Convention>	getTraitClass()
void	registerConverterRule(RelOptPlanner planner, ConverterRule converterRule) Provides notification of the registration of a particular ConverterRule with a RelOptPlanner.

Methods inherited from class org.apache.calcite.plan.RelTraitDef

canConvert, canonize, canonizeComposite, multiple

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

public static final ConventionTraitDef INSTANCE

conversionCache

private final com.google.common.cache.LoadingCache<RelOptPlanner,ConventionTraitDef.ConversionData> conversionCache

Weak-key cache of RelOptPlanner to ConversionData. The idea is that when the planner goes away, so does the cache entry.

Constructor Detail

ConventionTraitDef

private ConventionTraitDef()

Method Detail

getTraitClass

public Class<Convention> getTraitClass()

Specified by:

getTraitClass in class RelTraitDef<Convention>

Returns:

the specific RelTrait type associated with this RelTraitDef.

getSimpleName

public String getSimpleName()

Specified by:

getSimpleName in class RelTraitDef<Convention>

Returns:

a simple name for this RelTraitDef (for use in RelNode.explain(org.apache.calcite.rel.RelWriter)).

getDefault

public Convention getDefault()

Description copied from class: RelTraitDef

Returns the default member of this trait.

Specified by:

getDefault in class RelTraitDef<Convention>

registerConverterRule

public void registerConverterRule(RelOptPlanner planner,
                                  ConverterRule converterRule)

Description copied from class: RelTraitDef

Provides notification of the registration of a particular ConverterRule with a RelOptPlanner. The default implementation does nothing.

Overrides:

registerConverterRule in class RelTraitDef<Convention>

Parameters:

planner - the planner registering the rule

converterRule - the registered converter rule

deregisterConverterRule

public void deregisterConverterRule(RelOptPlanner planner,
                                    ConverterRule converterRule)

Description copied from class: RelTraitDef

Provides notification that a particular ConverterRule has been de-registered from a RelOptPlanner. The default implementation does nothing.

Overrides:

deregisterConverterRule in class RelTraitDef<Convention>

Parameters:

planner - the planner registering the rule

converterRule - the registered converter rule

convert

public RelNode convert(RelOptPlanner planner,
                       RelNode rel,
                       Convention toConvention,
                       boolean allowInfiniteCostConverters)

Description copied from class: RelTraitDef

Converts the given RelNode to the given RelTrait.

Specified by:

convert in class RelTraitDef<Convention>

Parameters:

planner - the planner requesting the conversion

rel - RelNode to convert

toConvention - RelTrait to convert to

allowInfiniteCostConverters - flag indicating whether infinite cost converters are allowed

Returns:

a converted RelNode or null if conversion is not possible

changeConvention

private RelNode changeConvention(RelNode rel,
                                 Convention source,
                                 Convention target,
                                 com.google.common.collect.Multimap<Pair<Convention,Convention>,ConverterRule> mapArcToConverterRule)

Tries to convert a relational expression to the target convention of an arc.

canConvert

public boolean canConvert(RelOptPlanner planner,
                          Convention fromConvention,
                          Convention toConvention)

Description copied from class: RelTraitDef

Tests whether the given RelTrait can be converted to another RelTrait.

Specified by:

canConvert in class RelTraitDef<Convention>

Parameters:

planner - the planner requesting the conversion test

fromConvention - the RelTrait to convert from

toConvention - the RelTrait to convert to

Returns:

true if fromTrait can be converted to toTrait

getConversionData

private ConventionTraitDef.ConversionData getConversionData(RelOptPlanner planner)