org.apache.hadoop.hbase.filter

Class FilterWrapper

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterWrapper

@InterfaceAudience.Private
public final class FilterWrapper
extends Filter

This is a Filter wrapper class which is used in the server side. Some filter related hooks can be defined in this wrapper. The only way to create a FilterWrapper instance is passing a client side Filter instance through Scan.getFilter().

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	FilterWrapper.FilterRowRetCode

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
FilterWrapper(Filter filter)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	filterAllRemaining() If this returns true, the scan will terminate.
Filter.ReturnCode	filterKeyValue(Cell v) A way to filter based on the column family, column qualifier and/or the column value.
boolean	filterRow() Last chance to veto row based on previous Filter.filterKeyValue(Cell) calls.
void	filterRowCells(List<Cell> kvs) Chance to alter the list of Cells to be submitted.
FilterWrapper.FilterRowRetCode	filterRowCellsWithRet(List<Cell> kvs)
boolean	filterRowKey(byte[] buffer, int offset, int length) Filters a row based on the row key.
Cell	getNextCellHint(Cell currentKV) 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.
KeyValue	getNextKeyHint(KeyValue currentKV) Deprecated.
boolean	hasFilterRow() Primarily used to check for conflicts with scans(such as scans that do not read a full row at a time).
boolean	isFamilyEssential(byte[] name) Check that given column family is essential for filter to check row.
static FilterWrapper	parseFrom(byte[] pbBytes)
void	reset() Reset the state of the filter between rows.
byte[]	toByteArray() TODO: JAVADOC Concrete implementers can signal a failure condition in their code by throwing an IOException.
KeyValue	transform(KeyValue currentKV) Deprecated.
Cell	transformCell(Cell v) Give the filter a chance to transform the passed KeyValue.

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, toString, wait, wait, wait

Constructor Detail

FilterWrapper

public FilterWrapper(Filter filter)

Method Detail

toByteArray

public byte[] toByteArray()
                   throws IOException

Description copied from class: Filter

TODO: JAVADOC Concrete implementers can signal a failure condition in their code by throwing an IOException.

Specified by:

toByteArray in class Filter

Returns:

The filter serialized using pb

Throws:

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

parseFrom

public static FilterWrapper parseFrom(byte[] pbBytes)
                               throws DeserializationException

Parameters:

pbBytes - A pb serialized FilterWrapper instance

Returns:

An instance of FilterWrapper made from bytes

Throws:

DeserializationException

See Also:

toByteArray()

reset

public void reset()
           throws IOException

Description copied from class: Filter

Reset the state of the filter between rows. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Specified by:

reset in class Filter

Throws:

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

filterAllRemaining

public boolean filterAllRemaining()
                           throws IOException

Description copied from class: Filter

If this returns true, the scan will terminate. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Specified by:

filterAllRemaining in class Filter

Returns:

true to end scan, false to continue.

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: Filter

Last chance to veto row based on previous Filter.filterKeyValue(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.

Specified by:

filterRow in class Filter

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.

getNextKeyHint

@Deprecated
public KeyValue getNextKeyHint(KeyValue currentKV)
                        throws IOException

Deprecated.

This method is deprecated and you should override Cell getNextKeyHint(Cell) instead.

Specified by:

getNextKeyHint in class Filter

Returns:

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

Throws:

IOException - Function is Deprecated. Use Filter.getNextCellHint(Cell) instead.

getNextCellHint

public Cell getNextCellHint(Cell currentKV)
                     throws IOException

Description copied from class: Filter

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.

Specified by:

getNextCellHint in class Filter

Returns:

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

Throws:

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

filterRowKey

public boolean filterRowKey(byte[] buffer,
                   int offset,
                   int length)
                     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.filterKeyValue(Cell) below. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Specified by:

filterRowKey in class Filter

Parameters:

buffer - buffer containing row key

offset - offset into buffer where row key starts

length - length of the row key

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

public Filter.ReturnCode filterKeyValue(Cell v)
                                 throws IOException

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:

v - the Cell in question

Returns:

code as described below

Throws:

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

See Also:

Filter.ReturnCode

transformCell

public Cell transformCell(Cell v)
                   throws IOException

Description copied from class: Filter

Give the filter a chance to transform the passed KeyValue. If the Cell is changed a new Cell object must be returned.

Specified by:

transformCell in class Filter

Parameters:

v - the KeyValue in question

Returns:

the changed KeyValue

Throws:

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

See Also:

The transformed KeyValue is what is eventually returned to the client. Most filters will return the passed KeyValue unchanged., for an example of a transformation. Concrete implementers can signal a failure condition in their code by throwing an {@link IOException}.

transform

@Deprecated
public KeyValue transform(KeyValue currentKV)
                   throws IOException

Deprecated.

WARNING: please to not override this method. Instead override transformCell(Cell). This is for transition from 0.94 -> 0.96

Specified by:

transform in class Filter

Throws:

IOException

hasFilterRow

public boolean hasFilterRow()

Description copied from class: Filter

Primarily used to check for conflicts with scans(such as scans that do not read a full row at a time).

Specified by:

hasFilterRow in class Filter

Returns:

True if this filter actively uses filterRowCells(List) or filterRow().

filterRowCells

public void filterRowCells(List<Cell> kvs)
                    throws IOException

Description copied from class: Filter

Chance to alter the list of Cells to be submitted. Modifications to the list will carry on Concrete implementers can signal a failure condition in their code by throwing an IOException.

Specified by:

filterRowCells in class Filter

Parameters:

kvs - the list of Cells to be filtered

Throws:

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

filterRowCellsWithRet

public FilterWrapper.FilterRowRetCode filterRowCellsWithRet(List<Cell> kvs)
                                                     throws IOException

Throws:

IOException

isFamilyEssential

public boolean isFamilyEssential(byte[] name)
                          throws IOException

Description copied from class: Filter

Check that given column family is essential for filter to check row. Most filters always return true here. But some could have more sophisticated logic which could significantly reduce scanning process by not even touching columns until we are 100% sure that it's data is needed in result. Concrete implementers can signal a failure condition in their code by throwing an IOException.

Specified by:

isFamilyEssential in class Filter

Throws:

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