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

Class ColumnsScanFramework

java.lang.Object

org.apache.drill.exec.physical.impl.scan.framework.ManagedScanFramework

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

org.apache.drill.exec.physical.impl.scan.columns.ColumnsScanFramework

All Implemented Interfaces:

ScanOperatorEvents

public class ColumnsScanFramework
extends FileScanFramework

Scan framework for a file that supports the special "columns" column.

The logic here is a bit tricky. The CSV (really, "compliant text") reader operates in multiple modes. If a header is required, then the columns array is not allowed. If the header is not loaded, then the columns array must be used.

This class combines the above semantics with the projection list from the query. It handles things like two appearances of the unadorned columns identifier, the use of the columns identifier when it is not allowed, etc.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ColumnsScanFramework.ColumnsScanBuilder
static class	ColumnsScanFramework.ColumnsSchemaNegotiatorImpl	Implementation of the columns array schema negotiator.

Nested classes/interfaces inherited from class org.apache.drill.exec.physical.impl.scan.file.FileScanFramework

FileScanFramework.FileReaderFactory, FileScanFramework.FileRowSetContext, FileScanFramework.FileScanBuilder, FileScanFramework.FileSchemaNegotiator, FileScanFramework.FileSchemaNegotiatorImpl

Nested classes/interfaces inherited from class org.apache.drill.exec.physical.impl.scan.framework.ManagedScanFramework

ManagedScanFramework.ReaderFactory, ManagedScanFramework.ScanFrameworkBuilder

Field Summary

Fields

Modifier and Type	Field	Description
static final String	COLUMNS_COL
protected ColumnsArrayManager	columnsArrayManager

Fields inherited from class org.apache.drill.exec.physical.impl.scan.framework.ManagedScanFramework

builder, context, readerFactory, scanOrchestrator

Constructor Summary

Constructors

Constructor	Description
ColumnsScanFramework(ColumnsScanFramework.ColumnsScanBuilder builder)

Method Summary

Modifier and Type	Method	Description
static TupleMetadata	columnsSchema()
protected void	configure()
protected SchemaNegotiatorImpl	newNegotiator()

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

fileSystem, nextSplit, open, options

Methods inherited from class org.apache.drill.exec.physical.impl.scan.framework.ManagedScanFramework

bind, close, context, errorContext, nextReader, outputSchema, scanOrchestrator

Methods inherited from class java.lang.Object

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

Field Details

COLUMNS_COL

public static final String COLUMNS_COL

See Also:

• Constant Field Values

columnsArrayManager

protected ColumnsArrayManager columnsArrayManager

Constructor Details

ColumnsScanFramework

public ColumnsScanFramework(ColumnsScanFramework.ColumnsScanBuilder builder)

Method Details

configure

protected void configure()

Overrides:

configure in class FileScanFramework

newNegotiator

protected SchemaNegotiatorImpl newNegotiator()

Overrides:

newNegotiator in class FileScanFramework

columnsSchema

public static TupleMetadata columnsSchema()