org.apache.hadoop.hbase.filter

Class SkipFilter

java.lang.Object

org.apache.hadoop.hbase.filter.Filter

org.apache.hadoop.hbase.filter.FilterBase

org.apache.hadoop.hbase.filter.SkipFilter

@InterfaceAudience.Public
public class SkipFilter
extends FilterBase

A wrapper filter that filters an entire row if any of the Cell checks do not pass.

For example, if all columns in a row represent weights of different things, with the values being the actual weights, and we want to filter out the entire row if any of its weights are zero. In this case, we want to prevent rows from being emitted if a single key is filtered. Combine this filter with a ValueFilter:

scan.setFilter(new SkipFilter(new ValueFilter(CompareOp.NOT_EQUAL, new BinaryComparator(Bytes.toBytes(0)))); Any row which contained a column whose value was 0 will be filtered out (since ValueFilter will not pass that Cell). Without this filter, the other non-zero valued columns in the row would still be emitted.

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
private Filter	filter
private boolean	filterRow

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

reversed

Constructor Summary

Constructors

Constructor and Description
SkipFilter(Filter filter)

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 void	changeFR(boolean value)
boolean	equals(Object obj)
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.
boolean	filterRowKey(Cell cell) Filters a row based on the row key.
Filter	getFilter()
boolean	hasFilterRow() Fitlers that never filter by modifying the returned List of Cells can inherit this implementation that does nothing.
int	hashCode()
boolean	isFamilyEssential(byte[] name) By default, we require all scan's column families to be present.
static SkipFilter	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.
Cell	transformCell(Cell v) By default no transformation takes place Give the filter a chance to transform the passed KeyValue.

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

createFilterFromArguments, filterAllRemaining, filterRowCells, filterRowKey, getNextCellHint

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

filterRow

private boolean filterRow

filter

private Filter filter

Constructor Detail

SkipFilter

public SkipFilter(Filter filter)

Method Detail

getFilter

public Filter getFilter()

reset

public void reset()
           throws IOException

Description copied from class: 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 FilterBase

Throws:

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

changeFR

private void changeFR(boolean value)

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)
                                             throws IOException

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

Throws:

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

See Also:

Filter.ReturnCode

filterCell

public Filter.ReturnCode filterCell(Cell c)
                             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, 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

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: FilterBase

By default no transformation takes place Give the filter a chance to transform the passed KeyValue. If the Cell is changed a new Cell object must be returned.

Overrides:

transformCell in class FilterBase

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}.

filterRow

public boolean filterRow()

Description copied from class: 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 FilterBase

Returns:

true to exclude row, false to include row.

hasFilterRow

public boolean hasFilterRow()

Description copied from class: FilterBase

Fitlers that never filter by modifying the returned List of Cells can inherit this implementation that does nothing. Primarily used to check for conflicts with scans(such as scans that do not read a full row at a time).

Overrides:

hasFilterRow in class FilterBase

Returns:

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

toByteArray

public byte[] toByteArray()
                   throws IOException

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

Throws:

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

parseFrom

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

Parameters:

pbBytes - A pb serialized SkipFilter instance

Returns:

An instance of SkipFilter 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.

isFamilyEssential

public boolean isFamilyEssential(byte[] name)
                          throws IOException

Description copied from class: FilterBase

By default, we require all scan's column families to be present. Our subclasses may be more precise. 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.

Overrides:

isFamilyEssential in class FilterBase

Throws:

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

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