public class MetadataFactoryImpl extends Object implements MetadataFactory
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.
Modifier and Type | Field and Description |
---|---|
static UnboundMetadata<Metadata> |
DUMMY |
Constructor and Description |
---|
MetadataFactoryImpl(RelMetadataProvider provider) |
Modifier and Type | Method and Description |
---|---|
<M extends Metadata> |
query(RelNode rel,
RelMetadataQuery mq,
Class<M> metadataClazz)
Returns a metadata interface to get a particular kind of metadata
from a particular relational expression.
|
public static final UnboundMetadata<Metadata> DUMMY
public MetadataFactoryImpl(RelMetadataProvider provider)
public <M extends Metadata> M query(RelNode rel, RelMetadataQuery mq, Class<M> metadataClazz)
MetadataFactory
query
in interface MetadataFactory
M
- Metadata typerel
- Relational expressionmq
- Metadata querymetadataClazz
- Metadata classrel
and query
Copyright © 2012–2018 The Apache Software Foundation. All rights reserved.