Package org.apache.druid.data.input

Class ColumnsFilter

java.lang.Object

org.apache.druid.data.input.ColumnsFilter

Direct Known Subclasses:

ColumnsFilter.ExclusionBased, ColumnsFilter.InclusionBased

public abstract class ColumnsFilter
extends Object

Used by some InputSourceReader implementations in order to know what columns will need to be read out of the InputRow objects they create. This is meant to be useful as an optimization: if we're reading from a columnar data format, then when a column isn't going to be needed, we shouldn't read it.

See Also:

• accepts objects of this class

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ColumnsFilter.ExclusionBased
static class	ColumnsFilter.InclusionBased

Constructor Summary

Constructors

Constructor	Description
ColumnsFilter()

Method Summary

Modifier and Type	Method	Description
static ColumnsFilter	all()	Accepts all columns.
abstract boolean	apply(String column)	Check if a column should be included or not.
static ColumnsFilter	exclusionBased(Set<String> exclusions)	Accepts all columns, except those on a specific list.
static ColumnsFilter	inclusionBased(Set<String> inclusions)	Accepts a specific list of columns.
abstract ColumnsFilter	plus(String column)	Returns a new filter with a particular column added.

Methods inherited from class java.lang.Object

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

Constructor Details

ColumnsFilter

public ColumnsFilter()

Method Details

all

public static ColumnsFilter all()

Accepts all columns.

inclusionBased

public static ColumnsFilter inclusionBased(Set<String> inclusions)

Accepts a specific list of columns.

exclusionBased

public static ColumnsFilter exclusionBased(Set<String> exclusions)

Accepts all columns, except those on a specific list.

apply

public abstract boolean apply(String column)

Check if a column should be included or not.

plus

public abstract ColumnsFilter plus(String column)

Returns a new filter with a particular column added. The returned filter will return true from apply(java.lang.String) on this column.