org.apache.drill.exec.physical.impl.scan.file

Class MetadataColumn

java.lang.Object

org.apache.drill.exec.physical.impl.scan.project.ResolvedColumn

org.apache.drill.exec.physical.impl.scan.file.MetadataColumn

All Implemented Interfaces:

ColumnProjection, ConstantColumnLoader.ConstantColumnSpec

Direct Known Subclasses:

FileMetadataColumn, PartitionColumn

public abstract class MetadataColumn
extends ResolvedColumn
implements ConstantColumnLoader.ConstantColumnSpec

Resolved value for a metadata column (implicit file or partition column.) Resolution here means identifying a value for the column.

Constructor Summary

Constructors

Constructor and Description
MetadataColumn(String name, TypeProtos.MajorType type, String value, VectorSource source, int sourceIndex)

Method Summary

Modifier and Type	Method and Description
String	name() The name of the column as it appears in the output row (record batch.)
abstract MetadataColumn	resolve(FileMetadata fileInfo, VectorSource source, int sourceIndex)
MaterializedField	schema() Return the type of this column.
String	toString()
String	value()

Methods inherited from class org.apache.drill.exec.physical.impl.scan.project.ResolvedColumn

metadata, project, source, sourceIndex

Methods inherited from class java.lang.Object

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

Constructor Detail

MetadataColumn

public MetadataColumn(String name,
                      TypeProtos.MajorType type,
                      String value,
                      VectorSource source,
                      int sourceIndex)

Method Detail

schema

public MaterializedField schema()

Description copied from class: ResolvedColumn

Return the type of this column. Used primarily by the schema smoothing mechanism.

Specified by:

schema in interface ConstantColumnLoader.ConstantColumnSpec

Specified by:

schema in class ResolvedColumn

Returns:

the MaterializedField representation of this column

value

public String value()

Specified by:

value in interface ConstantColumnLoader.ConstantColumnSpec

name

public String name()

Description copied from interface: ColumnProjection

The name of the column as it appears in the output row (record batch.)

Specified by:

name in interface ColumnProjection

Specified by:

name in interface ConstantColumnLoader.ConstantColumnSpec

Returns:

the output column name

resolve

public abstract MetadataColumn resolve(FileMetadata fileInfo,
                                       VectorSource source,
                                       int sourceIndex)

toString

public String toString()

Overrides:

toString in class Object