org.apache.hadoop.hbase.filter

Class KeyOnlyFilter

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterBase

org.apache.hadoop.hbase.filter.KeyOnlyFilter

@InterfaceAudience.Public
@InterfaceStability.Stable
public class KeyOnlyFilter
extends FilterBase

A filter that will only return the key component of each KV (the value will be rewritten as empty).

This filter can be used to grab all of the keys without having to also grab the values.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.filter.Filter

Filter.ReturnCode

Constructor Summary

Constructors

Constructor and Description
KeyOnlyFilter()
KeyOnlyFilter(boolean lenAsVal)

Method Summary

Methods

Modifier and Type	Method and Description
static Filter	createFilterFromArguments(ArrayList<byte[]> filterArguments)
static KeyOnlyFilter	parseFrom(byte[] pbBytes)
byte[]	toByteArray() Return length 0 byte array for Filters that don't require special serialization
Cell	transformCell(Cell kv) By default no transformation takes place

Methods inherited from class org.apache.hadoop.hbase.filter.FilterBase

filterAllRemaining, filterKeyValue, filterRow, filterRow, filterRowCells, filterRowKey, getNextCellHint, getNextKeyHint, hasFilterRow, isFamilyEssential, reset, toString, transform

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyOnlyFilter

public KeyOnlyFilter()

KeyOnlyFilter

public KeyOnlyFilter(boolean lenAsVal)

Method Detail

transformCell

public Cell transformCell(Cell kv)

Description copied from class: FilterBase

By default no transformation takes place

Overrides:

transformCell in class FilterBase

Parameters:

kv - the KeyValue in question

Returns:

the changed KeyValue

See Also:

The transformed KeyValue is what is eventually returned to the client. Most filters will return the passed KeyValue unchanged., for an example of a transformation. Concrete implementers can signal a failure condition in their code by throwing an {@link IOException}.

createFilterFromArguments

public static Filter createFilterFromArguments(ArrayList<byte[]> filterArguments)

toByteArray

public byte[] toByteArray()

Description copied from class: FilterBase

Return length 0 byte array for Filters that don't require special serialization

Overrides:

toByteArray in class FilterBase

Returns:

The filter serialized using pb

parseFrom

public static KeyOnlyFilter parseFrom(byte[] pbBytes)
                               throws DeserializationException

Parameters:

pbBytes - A pb serialized KeyOnlyFilter instance

Returns:

An instance of KeyOnlyFilter made from bytes

Throws:

DeserializationException

See Also:

toByteArray()