org.apache.calcite.plan.hep

Class HepRelMetadataProvider

java.lang.Object

org.apache.calcite.plan.hep.HepRelMetadataProvider

All Implemented Interfaces:

RelMetadataProvider

class HepRelMetadataProvider
extends Object
implements RelMetadataProvider

HepRelMetadataProvider implements the RelMetadataProvider interface by combining metadata from the rels inside of a HepRelVertex.

Constructor Summary

Constructors

Constructor and Description
HepRelMetadataProvider()

Method Summary

Modifier and Type	Method and Description
<M extends Metadata> UnboundMetadata<M>	apply(Class<? extends RelNode> relClass, Class<? extends M> metadataClass) Retrieves metadata of a particular type and for a particular sub-class of relational expression.
boolean	equals(Object obj)
<M extends Metadata> com.google.common.collect.Multimap<Method,MetadataHandler<M>>	handlers(MetadataDef<M> def)
int	hashCode()

Methods inherited from class java.lang.Object

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

Constructor Detail

HepRelMetadataProvider

HepRelMetadataProvider()

Method Detail

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

apply

public <M extends Metadata> UnboundMetadata<M> apply(Class<? extends RelNode> relClass,
                                                     Class<? extends M> metadataClass)

Description copied from interface: RelMetadataProvider

Retrieves metadata of a particular type and for a particular sub-class of relational expression.

The object returned is a function. It can be applied to a relational expression of the given type to create a metadata object.

For example, you might call

 RelMetadataProvider provider;
 LogicalFilter filter;
 RexNode predicate;
 Function<RelNode, Metadata> function =
   provider.apply(LogicalFilter.class, Selectivity.class};
 Selectivity selectivity = function.apply(filter);
 Double d = selectivity.selectivity(predicate);
 

Specified by:

apply in interface RelMetadataProvider

Parameters:

relClass - Type of relational expression

metadataClass - Type of metadata

Returns:

Function that will field a metadata instance; or null if this provider cannot supply metadata of this type

handlers

public <M extends Metadata> com.google.common.collect.Multimap<Method,MetadataHandler<M>> handlers(MetadataDef<M> def)

Specified by:

handlers in interface RelMetadataProvider