Package org.apache.calcite.plan.volcano

Class VolcanoRelMetadataProvider

java.lang.Object

org.apache.calcite.plan.volcano.VolcanoRelMetadataProvider

All Implemented Interfaces:

RelMetadataProvider

public class VolcanoRelMetadataProvider
extends java.lang.Object
implements RelMetadataProvider

VolcanoRelMetadataProvider implements the RelMetadataProvider interface by combining metadata from the rels making up an equivalence class.

Constructor Summary

Constructors

Constructor	Description
VolcanoRelMetadataProvider()

Method Summary

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

VolcanoRelMetadataProvider

public VolcanoRelMetadataProvider()

Method Detail

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

apply

public <M extends Metadata> UnboundMetadata<M> apply(java.lang.Class<? extends RelNode> relClass,
                                                     java.lang.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<java.lang.reflect.Method,MetadataHandler<M>> handlers(MetadataDef<M> def)

Specified by:

handlers in interface RelMetadataProvider