org.apache.hadoop.hbase.filter

Class FirstKeyOnlyFilter

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterBase

org.apache.hadoop.hbase.filter.FirstKeyOnlyFilter

Direct Known Subclasses:

FirstKeyValueMatchingQualifiersFilter

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

A filter that will only return the first KV from each row.

This filter can be used to more efficiently perform row count operations.

Nested Class Summary

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

Filter.ReturnCode

Constructor Summary

Constructors

Constructor and Description
FirstKeyOnlyFilter()

Method Summary

Methods

Modifier and Type	Method and Description
static Filter	createFilterFromArguments(ArrayList<byte[]> filterArguments)
Filter.ReturnCode	filterKeyValue(Cell v) Filters that dont filter by key value can inherit this implementation that includes all Cells.
protected boolean	hasFoundKV()
static FirstKeyOnlyFilter	parseFrom(byte[] pbBytes)
void	reset() Filters that are purely stateless and do nothing in their reset() methods can inherit this null/empty implementation.
protected void	setFoundKV(boolean value)
byte[]	toByteArray() Return length 0 byte array for Filters that don't require special serialization

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

filterAllRemaining, filterRow, filterRow, filterRowCells, filterRowKey, getNextCellHint, getNextKeyHint, hasFilterRow, isFamilyEssential, toString, transform, transformCell

Methods inherited from class java.lang.Object

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

Constructor Detail

FirstKeyOnlyFilter

public FirstKeyOnlyFilter()

Method Detail

reset

public void reset()

Description copied from class: FilterBase

Filters that are purely stateless and do nothing in their reset() methods can inherit this null/empty implementation.

Overrides:

reset in class FilterBase

filterKeyValue

public Filter.ReturnCode filterKeyValue(Cell v)

Description copied from class: FilterBase

Filters that dont filter by key value can inherit this implementation that includes all Cells.

Overrides:

filterKeyValue in class FilterBase

Parameters:

v - the Cell in question

Returns:

code as described below

See Also:

Filter.ReturnCode

createFilterFromArguments

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

hasFoundKV

protected boolean hasFoundKV()

Returns:

true if first KV has been found.

setFoundKV

protected void setFoundKV(boolean value)

Parameters:

value - update foundKV flag with value.

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 FirstKeyOnlyFilter parseFrom(byte[] pbBytes)
                                    throws DeserializationException

Parameters:

pbBytes - A pb serialized FirstKeyOnlyFilter instance

Returns:

An instance of FirstKeyOnlyFilter made from bytes

Throws:

DeserializationException

See Also:

toByteArray()