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

Class AbstractUnresolvedColumn

java.lang.Object

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

All Implemented Interfaces:

ColumnProjection

Direct Known Subclasses:

AbstractUnresolvedColumn.UnresolvedColumn, AbstractUnresolvedColumn.UnresolvedWildcardColumn, UnresolvedColumnsArrayColumn

public abstract class AbstractUnresolvedColumn
extends Object
implements ColumnProjection

Represents a projected column that has not yet been bound to a table column, special column or a null column. Once bound, this column projection is replaced with the detailed binding.

Occurs in a scan-level projection to identify columns needed in the output batch. Once we see reader data, we create a ResolvedColumn to replace this unresolved form. The resolved form identifies how to map data from its source (reader, null column builder, etc.) to the output batch. Thus the columns here are placeholders to be rewritten once more data is available.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractUnresolvedColumn.UnresolvedColumn Represents an unresolved table column to be provided by the reader (or filled in with nulls.) May be associated with a provided schema column.
static class	AbstractUnresolvedColumn.UnresolvedWildcardColumn

Field Summary

Fields

Modifier and Type	Field and Description
protected RequestedColumn	inCol The original physical plan column to which this output column maps.

Constructor Summary

Constructors

Constructor and Description
AbstractUnresolvedColumn(RequestedColumn inCol)

Method Summary

Modifier and Type	Method and Description
RequestedColumn	element()
String	name() The name of the column as it appears in the output row (record batch.)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

inCol

protected final RequestedColumn inCol

The original physical plan column to which this output column maps. In some cases, multiple output columns map map the to the same "input" (to the projection process) column.

Constructor Detail

AbstractUnresolvedColumn

public AbstractUnresolvedColumn(RequestedColumn inCol)

Method Detail

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

Returns:

the output column name

element

public RequestedColumn element()

toString

public String toString()

Overrides:

toString in class Object