FilterWrapper (Apache HBase 1.4.11 API)

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

Nested Classes
Modifier and Type	Class and Description
`static class`	`FilterWrapper.FilterRowRetCode`

Field Summary
- Fields inherited from class org.apache.hadoop.hbase.filter.Filter
  reversed

Constructor Summary

Constructors
Constructor and Description

FilterWrapper(Filter filter)

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.

Class FilterWrapper

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.Filter

Methods inherited from class java.lang.Object

Constructor Detail

FilterWrapper

Method Detail

toByteArray

parseFrom

reset

filterAllRemaining

filterRow

getNextKeyHint

getNextCellHint

filterRowKey

filterKeyValue

transformCell

transform

hasFilterRow

filterRowCells

filterRowCellsWithRet

isFamilyEssential