org.apache.hadoop.hbase.filter

Class ColumnPaginationFilter

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterBase

org.apache.hadoop.hbase.filter.ColumnPaginationFilter

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

A filter, based on the ColumnCountGetFilter, takes two arguments: limit and offset. This filter can be used for row-based indexing, where references to other tables are stored across many columns, in order to efficient lookups and paginated results for end users. Only most recent versions are considered for pagination.

Nested Class Summary

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

Filter.ReturnCode

Constructor Summary

Constructors

Constructor and Description
ColumnPaginationFilter(int limit, byte[] columnOffset) Initializes filter with a string/bookmark based offset and limit.
ColumnPaginationFilter(int limit, int offset) Initializes filter with an integer offset and limit.

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.
byte[]	getColumnOffset()
int	getLimit()
Cell	getNextCellHint(Cell kv) Filters that are not sure which key must be next seeked to, can inherit this implementation that, by default, returns a null Cell.
int	getOffset()
static ColumnPaginationFilter	parseFrom(byte[] pbBytes)
void	reset() Filters that are purely stateless and do nothing in their reset() methods can inherit this null/empty implementation.
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, filterRow, filterRowCells, filterRowKey, getNextKeyHint, hasFilterRow, isFamilyEssential, transform, transformCell

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnPaginationFilter

public ColumnPaginationFilter(int limit,
                      int offset)

Initializes filter with an integer offset and limit. The offset is arrived at scanning sequentially and skipping entries. @limit number of columns are then retrieved. If multiple column families are involved, the columns may be spread across them.

Parameters:

limit - Max number of columns to return.

offset - The integer offset where to start pagination.

ColumnPaginationFilter

public ColumnPaginationFilter(int limit,
                      byte[] columnOffset)

Initializes filter with a string/bookmark based offset and limit. The offset is arrived at, by seeking to it using scanner hints. If multiple column families are involved, pagination starts at the first column family which contains @columnOffset. Columns are then retrieved sequentially upto @limit number of columns which maybe spread across multiple column families, depending on how the scan is setup.

Parameters:

limit - Max number of columns to return.

columnOffset - The string/bookmark offset on where to start pagination.

Method Detail

getLimit

public int getLimit()

Returns:

limit

getOffset

public int getOffset()

Returns:

offset

getColumnOffset

public byte[] getColumnOffset()

Returns:

columnOffset

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

getNextCellHint

public Cell getNextCellHint(Cell kv)

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.

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.

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

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 ColumnPaginationFilter parseFrom(byte[] pbBytes)
                                        throws DeserializationException

Parameters:

pbBytes - A pb serialized ColumnPaginationFilter instance

Returns:

An instance of ColumnPaginationFilter 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