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

Class FileMetadataColumn

java.lang.Object

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

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

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

All Implemented Interfaces:

ColumnProjection, ConstantColumnLoader.ConstantColumnSpec

public class FileMetadataColumn
extends MetadataColumn

Represents projection column which resolved to a file metadata (AKA "implicit") column such as "filename", "fqn", etc. These columns are "synthetic" added by the scan framework itself rather than "organic" coming from the scanned table.

Constructor Summary

Constructors

Constructor	Description
FileMetadataColumn(String name, FileMetadataColumnDefn defn)	Constructor for unresolved column.
FileMetadataColumn(String name, FileMetadataColumnDefn defn, FileMetadata fileInfo, VectorSource source, int sourceIndex)	Constructor for resolved column.

Method Summary

Modifier and Type	Method	Description
FileMetadataColumnDefn	defn()
MetadataColumn	resolve(FileMetadata fileInfo, VectorSource source, int sourceIndex)

Methods inherited from class org.apache.drill.exec.physical.impl.scan.file.MetadataColumn

name, schema, toString, 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 Details

FileMetadataColumn

public FileMetadataColumn(String name,
 FileMetadataColumnDefn defn,
 FileMetadata fileInfo,
 VectorSource source,
 int sourceIndex)

Constructor for resolved column. The column is resolved at the file level once we identify the file to which the column is bound.

Parameters:

name - name of the column as given in the projection list

defn - definition of the metadata column

fileInfo - description of the file used in this scan. Used to populate the value of this column on a per-file basis

source - handle to the a logical batch that holds the vectors to be populated in each row batch

sourceIndex - the location of the vector to populate

FileMetadataColumn

public FileMetadataColumn(String name,
 FileMetadataColumnDefn defn)

Constructor for unresolved column. A column is unresolved at the scan level: we know that this is a file metadata column, but we don't yet know the file to which to bind the column

Parameters:

name - name of the column as given in the projection list

defn - definition of the metadata column

Method Details

defn

public FileMetadataColumnDefn defn()

resolve

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

Specified by:

resolve in class MetadataColumn