FuzzyRowFilter (Apache HBase 2.5.12 API)

java.lang.Object
- org.apache.hadoop.hbase.filter.Filter
- - org.apache.hadoop.hbase.filter.FilterBase
  - - org.apache.hadoop.hbase.filter.FuzzyRowFilter

All Implemented Interfaces:

HintingFilter
```
@InterfaceAudience.Public
public class FuzzyRowFilter
extends org.apache.hadoop.hbase.filter.FilterBase
implements HintingFilter
```
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)

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

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`boolean`	`equals(Object obj)`
`boolean`	`filterAllRemaining()` Filters that never filter all remaining can inherit this implementation that never stops the filter early.
`Filter.ReturnCode`	`filterCell(Cell c)` A way to filter based on the column family, column qualifier and/or the column value.
`Filter.ReturnCode`	`filterKeyValue(Cell c)` Deprecated.
`boolean`	`filterRow()` Filters that never filter by rows based on previously gathered state from `Filter.filterCell(Cell)` can inherit this implementation that never filters a row.
`List<Pair<byte[],byte[]>>`	`getFuzzyKeys()` Returns the Fuzzy keys in the format expected by the constructor.
`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.
`int`	`hashCode()`
`static FuzzyRowFilter`	`parseFrom(byte[] pbBytes)` Parse a serialized representation of `FuzzyRowFilter`
`void`	`reset()` Filters that are purely stateless and do nothing in their reset() methods can inherit this null/empty implementation.
`byte[]`	`toByteArray()` Returns The filter serialized using pb
`String`	`toString()` Return filter's info for debugging and logging purpose.

Methods inherited from class org.apache.hadoop.hbase.filter.FilterBase
createFilterFromArguments, filterRowCells, filterRowKey, filterRowKey, hasFilterRow, isFamilyEssential, transformCell

Methods inherited from class org.apache.hadoop.hbase.filter.Filter
isReversed, setReversed

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - FuzzyRowFilter
```
public FuzzyRowFilter(List<Pair<byte[],byte[]>> fuzzyKeysData)
```
- Method Detail
  - getFuzzyKeys
```
public List<Pair<byte[],byte[]>> getFuzzyKeys()
```
    Returns the Fuzzy keys in the format expected by the constructor.
    
    Returns:
    
    the Fuzzy keys in the format expected by the constructor
  - filterKeyValue
```
@Deprecated
public Filter.ReturnCode filterKeyValue(Cell c)
```
    Deprecated.
    
    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.
    
    Overrides:
    
    filterKeyValue in class Filter
    
    Parameters:
    
    c - the Cell in question
    
    Returns:
    
    code as described below, Filter.ReturnCode.INCLUDE by default
    
    See Also:
    
    Filter.ReturnCode
  - reset
```
public void reset()
           throws IOException
```
    Description copied from class: org.apache.hadoop.hbase.filter.FilterBase
    
    Filters that are purely stateless and do nothing in their reset() methods can inherit this null/empty implementation. Reset the state of the filter between rows. Concrete implementers can signal a failure condition in their code by throwing an IOException.
    
    Overrides:
    
    reset in class org.apache.hadoop.hbase.filter.FilterBase
    
    Throws:
    
    IOException - in case an I/O or an filter specific failure needs to be signaled.
  - filterRow
```
public boolean filterRow()
                  throws IOException
```
    Description copied from class: org.apache.hadoop.hbase.filter.FilterBase
    
    Filters that never filter by rows based on previously gathered state from Filter.filterCell(Cell) can inherit this implementation that never filters a row. Last chance to veto row based on previous Filter.filterCell(Cell) calls. The filter needs to retain state then return a particular value for this call if they wish to exclude a row if a certain column is missing (for example). Concrete implementers can signal a failure condition in their code by throwing an IOException.
    
    Overrides:
    
    filterRow in class org.apache.hadoop.hbase.filter.FilterBase
    
    Returns:
    
    true to exclude row, false to include row.
    
    Throws:
    
    IOException - in case an I/O or an filter specific failure needs to be signaled.
  - filterCell
```
public Filter.ReturnCode filterCell(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, filterCell needs to be consistent with it. filterCell 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.
    
    Overrides:
    
    filterCell 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: org.apache.hadoop.hbase.filter.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 org.apache.hadoop.hbase.filter.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: org.apache.hadoop.hbase.filter.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 org.apache.hadoop.hbase.filter.FilterBase
    
    Returns:
    
    true to end scan, false to continue.
  - toByteArray
```
public byte[] toByteArray()
```
    Returns The filter serialized using pb
    
    Overrides:
    
    toByteArray in class org.apache.hadoop.hbase.filter.FilterBase
    
    Returns:
    
    The filter serialized using pb
  - parseFrom
```
public static FuzzyRowFilter parseFrom(byte[] pbBytes)
                                throws org.apache.hadoop.hbase.exceptions.DeserializationException
```
    Parse a serialized representation of FuzzyRowFilter
    
    Parameters:
    
    pbBytes - A pb serialized FuzzyRowFilter instance
    
    Returns:
    
    An instance of FuzzyRowFilter made from bytes
    
    Throws:
    
    org.apache.hadoop.hbase.exceptions.DeserializationException - if an error occurred
    
    See Also:
    
    toByteArray()
  - toString
```
public String toString()
```
    Description copied from class: org.apache.hadoop.hbase.filter.FilterBase
    
    Return filter's info for debugging and logging purpose.
    
    Overrides:
    
    toString in class org.apache.hadoop.hbase.filter.FilterBase
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object

Class FuzzyRowFilter

Nested Class Summary

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

Field Summary

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

Constructor Detail

FuzzyRowFilter

Method Detail

getFuzzyKeys

filterKeyValue

reset

filterRow

filterCell

getNextCellHint

filterAllRemaining

toByteArray

parseFrom

toString

equals

hashCode