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

Class ResolvedColumn

java.lang.Object

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

All Implemented Interfaces:

ColumnProjection

Direct Known Subclasses:

MetadataColumn, ResolvedDictColumn, ResolvedMapColumn, ResolvedNullColumn, ResolvedTableColumn

public abstract class ResolvedColumn
extends Object
implements ColumnProjection

A resolved column has a name, and a specification for how to project data from a source vector to a vector in the final output container. Describes the projection of a single column from an input to an output batch.

Although the table schema mechanism uses the newer "metadata" mechanism, resolved columns revert back to the original MajorType and MaterializedField mechanism used by the rest of Drill. Doing so loses a bit of additional information, but at present there is no way to export that information along with a serialized record batch; each operator must rediscover it after deserialization.

Constructor Summary

Constructors

Constructor	Description
ResolvedColumn(VectorSource source, int sourceIndex)
ResolvedColumn(ColumnMetadata outputCol, VectorSource source, int sourceIndex)

Method Summary

Modifier and Type	Method	Description
ColumnMetadata	metadata()
void	project(ResolvedTuple dest)
abstract MaterializedField	schema()	Return the type of this column.
VectorSource	source()
int	sourceIndex()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.drill.exec.physical.impl.scan.project.ColumnProjection

name

Constructor Details

ResolvedColumn

public ResolvedColumn(VectorSource source,
 int sourceIndex)

ResolvedColumn

public ResolvedColumn(ColumnMetadata outputCol,
 VectorSource source,
 int sourceIndex)

Method Details

source

public VectorSource source()

sourceIndex

public int sourceIndex()

metadata

public ColumnMetadata metadata()

schema

public abstract MaterializedField schema()

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

Returns:

the MaterializedField representation of this column

project

public void project(ResolvedTuple dest)