Package 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
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.
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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.hadoop.hbase.filter.Filter
Filter.ReturnCode
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Field Summary
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescription(package private) boolean
Returns true if and only if the fields of the filter that are serialized are equal to the corresponding fields in other.private void
changeFR
(boolean value) boolean
filterCell
(Cell c) A way to filter based on the column family, column qualifier and/or the column value.boolean
Filters that never filter by rows based on previously gathered state fromFilter.filterCell(Cell)
can inherit this implementation that never filters a row.boolean
filterRowKey
(Cell cell) Filters a row based on the row key.boolean
Filters 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) Parse a serialized representation ofSkipFilter
void
reset()
Filters that are purely stateless and do nothing in their reset() methods can inherit this null/empty implementation.byte[]
Returns The filter serialized using pbtoString()
Return filter's info for debugging and logging purpose.By default no transformation takes place By default no transformation takes place Give the filter a chance to transform the passed Cell.Methods inherited from class org.apache.hadoop.hbase.filter.FilterBase
createFilterFromArguments, filterAllRemaining, filterRowCells, getNextCellHint
Methods inherited from class org.apache.hadoop.hbase.filter.Filter
isReversed, setReversed
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Field Details
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filterRow
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filter
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Constructor Details
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SkipFilter
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Method Details
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getFilter
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reset
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 anIOException
.- Overrides:
reset
in classFilterBase
- Throws:
IOException
- in case an I/O or an filter specific failure needs to be signaled.
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changeFR
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filterRowKey
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 toFilter.filterCell(Cell)
below. IfFilter.filterAllRemaining()
returns true, thenFilter.filterRowKey(Cell)
should also return true. Concrete implementers can signal a failure condition in their code by throwing anIOException
.- Overrides:
filterRowKey
in classFilterBase
- 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.
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filterCell
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 returnsReturnCode.NEXT_ROW
, it should returnReturnCode.NEXT_ROW
untilFilter.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 anIOException
.- Overrides:
filterCell
in classFilter
- 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:
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transformCell
Description copied from class:FilterBase
By default no transformation takes place Give the filter a chance to transform the passed Cell. If the Cell is changed a new Cell object must be returned. NOTICE: Filter will be evaluate at server side so the returnedCell
must be anExtendedCell
, although it is marked as IA.Private.- Overrides:
transformCell
in classFilterBase
- Parameters:
v
- the Cell in question- Returns:
- the changed Cell
- Throws:
IOException
- in case an I/O or an filter specific failure needs to be signaled.- See Also:
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filterRow
Description copied from class:FilterBase
Filters that never filter by rows based on previously gathered state fromFilter.filterCell(Cell)
can inherit this implementation that never filters a row. Last chance to veto row based on previousFilter.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 anIOException
.- Overrides:
filterRow
in classFilterBase
- Returns:
- true to exclude row, false to include row.
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hasFilterRow
Description copied from class:FilterBase
Filters 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 classFilterBase
- Returns:
- True if this filter actively uses filterRowCells(List) or filterRow().
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toByteArray
Returns The filter serialized using pb- Overrides:
toByteArray
in classFilterBase
- Returns:
- The filter serialized using pb
- Throws:
IOException
- in case an I/O or an filter specific failure needs to be signaled.
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parseFrom
Parse a serialized representation ofSkipFilter
- Parameters:
pbBytes
- A pb serializedSkipFilter
instance- Returns:
- An instance of
SkipFilter
made frombytes
- Throws:
DeserializationException
- if an error occurred- See Also:
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areSerializedFieldsEqual
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.- Overrides:
areSerializedFieldsEqual
in classFilterBase
- 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.
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isFamilyEssential
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 anIOException
.- Overrides:
isFamilyEssential
in classFilterBase
- Throws:
IOException
- in case an I/O or an filter specific failure needs to be signaled.
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toString
Description copied from class:FilterBase
Return filter's info for debugging and logging purpose.- Overrides:
toString
in classFilterBase
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equals
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hashCode
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