org.apache.calcite.rel.metadata

Class MetadataFactoryImpl

java.lang.Object

org.apache.calcite.rel.metadata.MetadataFactoryImpl

All Implemented Interfaces:

MetadataFactory

public class MetadataFactoryImpl
extends Object
implements MetadataFactory

Implementation of MetadataFactory that gets providers from a RelMetadataProvider and stores them in a cache.

The cache does not store metadata. It remembers which providers can provide which kinds of metadata, for which kinds of relational expressions.

Field Summary

Fields

Modifier and Type	Field and Description
static com.google.common.base.Function<RelNode,Metadata>	DUMMY

Constructor Summary

Constructors

Constructor and Description
MetadataFactoryImpl(RelMetadataProvider provider)

Method Summary

Methods

Modifier and Type	Method and Description
<T extends Metadata> T	query(RelNode rel, Class<T> clazz) Returns a metadata interface to get a particular kind of metadata from a particular relational expression.

Methods inherited from class java.lang.Object

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

Field Detail

DUMMY

public static final com.google.common.base.Function<RelNode,Metadata> DUMMY

Constructor Detail

MetadataFactoryImpl

public MetadataFactoryImpl(RelMetadataProvider provider)

Method Detail

query

public <T extends Metadata> T query(RelNode rel,
                           Class<T> clazz)

Description copied from interface: MetadataFactory

Returns a metadata interface to get a particular kind of metadata from a particular relational expression. Returns null if that kind of metadata is not available.

Specified by:

query in interface MetadataFactory