ColumnsFilter (druid-processing 30.0.1 API)

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

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
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 Detail
  - ColumnsFilter
```
public ColumnsFilter()
```
- Method Detail
  - 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.