org.apache.hadoop.hbase.filter

Class FuzzyRowFilter

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterBase

org.apache.hadoop.hbase.filter.FuzzyRowFilter

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class FuzzyRowFilter
extends FilterBase

This is optimized version of a standard FuzzyRowFilter Filters data based on fuzzy row key. Performs fast-forwards during scanning. It takes pairs (row key, fuzzy info) to match row keys. Where fuzzy info is a byte array with 0 or 1 as its values:

• 0 - means that this byte in provided row key is fixed, i.e. row key's byte at same position must match
• 1 - means that this byte in provided row key is NOT fixed, i.e. row key's byte at this position can be different from the one in provided row key

Example: Let's assume row key format is userId_actionId_year_month. Length of userId is fixed and is 4, length of actionId is 2 and year and month are 4 and 2 bytes long respectively. Let's assume that we need to fetch all users that performed certain action (encoded as "99") in Jan of any year. Then the pair (row key, fuzzy info) would be the following: row key = "????_99_????_01" (one can use any value instead of "?") fuzzy info = "\x01\x01\x01\x01\x00\x00\x00\x00\x01\x01\x01\x01\x00\x00\x00" I.e. fuzzy info tells the matching mask is "????_99_????_01", where at ? can be any value.

Nested Class Summary

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

Filter.ReturnCode

Field Summary

Fields inherited from class org.apache.hadoop.hbase.filter.Filter

reversed

Constructor Summary

Constructors

Constructor and Description
FuzzyRowFilter(List<Pair<byte[],byte[]>> fuzzyKeysData)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	filterAllRemaining() Filters that never filter all remaining can inherit this implementation that never stops the filter early.
Filter.ReturnCode	filterKeyValue(Cell c) A way to filter based on the column family, column qualifier and/or the column value.
Cell	getNextCellHint(Cell currentCell) Filters that are not sure which key must be next seeked to, can inherit this implementation that, by default, returns a null Cell.
static FuzzyRowFilter	parseFrom(byte[] pbBytes)
byte[]	toByteArray() Return length 0 byte array for Filters that don't require special serialization
String	toString() Return filter's info for debugging and logging purpose.

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

createFilterFromArguments, filterRow, filterRowCells, filterRowKey, getNextKeyHint, hasFilterRow, isFamilyEssential, reset, transform, transformCell

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

isReversed, setReversed

Methods inherited from class java.lang.Object

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

Constructor Detail

FuzzyRowFilter

public FuzzyRowFilter(List<Pair<byte[],byte[]>> fuzzyKeysData)

Method Detail

filterKeyValue

public Filter.ReturnCode filterKeyValue(Cell c)

Description copied from class: Filter

A way to filter based on the column family, column qualifier and/or the column value. Return code is described below. This allows filters to filter only certain number of columns, then terminate without matching ever column. If filterRowKey returns true, filterKeyValue needs to be consistent with it. filterKeyValue can assume that filterRowKey has already been called for the row. If your filter returns ReturnCode.NEXT_ROW, it should return ReturnCode.NEXT_ROW until Filter.reset() is called just in case the caller calls for the next row. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Specified by:

filterKeyValue in class Filter

Parameters:

c - the Cell in question

Returns:

code as described below

See Also:

Filter.ReturnCode

getNextCellHint

public Cell getNextCellHint(Cell currentCell)

Description copied from class: FilterBase

Filters that are not sure which key must be next seeked to, can inherit this implementation that, by default, returns a null Cell. If the filter returns the match code SEEK_NEXT_USING_HINT, then it should also tell which is the next key it must seek to. After receiving the match code SEEK_NEXT_USING_HINT, the QueryMatcher would call this function to find out which key it must next seek to. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

getNextCellHint in class FilterBase

Returns:

KeyValue which must be next seeked. return null if the filter is not sure which key to seek to next.

filterAllRemaining

public boolean filterAllRemaining()

Description copied from class: FilterBase

Filters that never filter all remaining can inherit this implementation that never stops the filter early. If this returns true, the scan will terminate. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

filterAllRemaining in class FilterBase

Returns:

true to end scan, false to continue.

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 FuzzyRowFilter parseFrom(byte[] pbBytes)
                                throws DeserializationException

Parameters:

pbBytes - A pb serialized FuzzyRowFilter instance

Returns:

An instance of FuzzyRowFilter made from bytes

Throws:

DeserializationException

See Also:

toByteArray()

toString

public String toString()

Description copied from class: FilterBase

Return filter's info for debugging and logging purpose.

Overrides:

toString in class FilterBase