org.apache.hadoop.hbase.filter

Class ColumnPrefixFilter

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterBase

org.apache.hadoop.hbase.filter.ColumnPrefixFilter

@InterfaceAudience.Public
public class ColumnPrefixFilter
extends FilterBase

This filter is used for selecting only those keys with columns that matches a particular prefix. For example, if prefix is 'an', it will pass keys with columns like 'and', 'anti' but not keys with columns like 'ball', 'act'.

Nested Class Summary

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

Filter.ReturnCode

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	prefix

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

reversed

Constructor Summary

Constructors

Constructor and Description
ColumnPrefixFilter(byte[] prefix)

Method Summary

Modifier and Type	Method and Description
(package private) boolean	areSerializedFieldsEqual(Filter o) Default implementation so that writers of custom filters aren't forced to implement.
private static int	compareQualifierPart(Cell cell, int length, byte[] prefix)
static Filter	createFilterFromArguments(ArrayList<byte[]> filterArguments)
boolean	equals(Object obj)
Filter.ReturnCode	filterCell(Cell cell) A way to filter based on the column family, column qualifier and/or the column value.
Filter.ReturnCode	filterColumn(Cell cell)
Filter.ReturnCode	filterKeyValue(Cell c) Deprecated.
boolean	filterRowKey(Cell cell) Filters a row based on the row key.
Cell	getNextCellHint(Cell cell) Filters that are not sure which key must be next seeked to, can inherit this implementation that, by default, returns a null Cell.
byte[]	getPrefix()
int	hashCode()
static ColumnPrefixFilter	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

filterAllRemaining, filterRow, filterRowCells, filterRowKey, hasFilterRow, isFamilyEssential, reset, 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

Field Detail

prefix

protected byte[] prefix

Constructor Detail

ColumnPrefixFilter

public ColumnPrefixFilter(byte[] prefix)

Method Detail

getPrefix

public byte[] getPrefix()

filterRowKey

public boolean filterRowKey(Cell cell)
                     throws IOException

Description copied from class: Filter

Filters a row based on the row key. If this returns true, the entire row will be excluded. If false, each KeyValue in the row will be passed to Filter.filterCell(Cell) below. If Filter.filterAllRemaining() returns true, then Filter.filterRowKey(Cell) should also return true. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Overrides:

filterRowKey in class FilterBase

Parameters:

cell - The first cell coming in the new row

Returns:

true, remove entire row, false, include the row (maybe).

Throws:

IOException - in case an I/O or an filter specific failure needs to be signaled.

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

filterCell

public Filter.ReturnCode filterCell(Cell cell)

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:

cell - the Cell in question

Returns:

code as described below

See Also:

Filter.ReturnCode

filterColumn

public Filter.ReturnCode filterColumn(Cell cell)

compareQualifierPart

private static int compareQualifierPart(Cell cell,
                                        int length,
                                        byte[] prefix)

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 ColumnPrefixFilter parseFrom(byte[] pbBytes)
                                    throws DeserializationException

Parameters:

pbBytes - A pb serialized ColumnPrefixFilter instance

Returns:

An instance of ColumnPrefixFilter made from bytes

Throws:

DeserializationException

See Also:

toByteArray()

areSerializedFieldsEqual

boolean areSerializedFieldsEqual(Filter o)

Description copied from class: FilterBase

Default implementation so that writers of custom filters aren't forced to implement.

Overrides:

areSerializedFieldsEqual in class FilterBase

Parameters:

o - the other filter to compare with

Returns:

true if and only if the fields of the filter that are serialized are equal to the corresponding fields in other. Used for testing.

getNextCellHint

public Cell getNextCellHint(Cell cell)

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.

toString

public String toString()

Description copied from class: FilterBase

Return filter's info for debugging and logging purpose.

Overrides:

toString in class FilterBase

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object