org.apache.calcite.rel.metadata

Class JaninoRelMetadataProvider

java.lang.Object

org.apache.calcite.rel.metadata.JaninoRelMetadataProvider

All Implemented Interfaces:

RelMetadataProvider

public class JaninoRelMetadataProvider
extends Object
implements RelMetadataProvider

Implementation of the RelMetadataProvider interface that generates a class that dispatches to the underlying providers.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JaninoRelMetadataProvider.NoHandler Exception that indicates there there should be a handler for this class but there is not.

Field Summary

Fields

Modifier and Type	Field and Description
static JaninoRelMetadataProvider	DEFAULT

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()
static JaninoRelMetadataProvider	of(RelMetadataProvider provider) Creates a JaninoRelMetadataProvider.
void	register(Iterable<Class<? extends RelNode>> classes) Registers some classes.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final JaninoRelMetadataProvider DEFAULT

Method Detail

of

public static JaninoRelMetadataProvider of(RelMetadataProvider provider)

Creates a JaninoRelMetadataProvider.

Parameters:

provider - Underlying provider

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

register

public void register(Iterable<Class<? extends RelNode>> classes)

Registers some classes. Does not flush the providers, but next time we need to generate a provider, it will handle all of these classes. So, calling this method reduces the number of times we need to re-generate.