Interface CellExtractor
- All Superinterfaces:
IndexExtractor
- All Known Subinterfaces:
CountingBloomFilter
- All Known Implementing Classes:
ArrayCountingBloomFilter
- Functional Interface:
- This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
Cell is used to
refer to these counts and their associated index. This class is the equivalent of the index extractor except
that it produces cells.
Note that a CellExtractor must not return duplicate indices and must be ordered.
Implementations must guarantee that:
- The IndexExtractor implementation returns unique ordered indices.
- The cells are produced in IndexExtractor order.
- For every value produced by the IndexExtractor there will be only one matching cell produced by the CellExtractor.
- The CellExtractor will not generate cells with indices that are not output by the IndexExtractor.
- The IndexExtractor will not generate indices that have a zero count for the cell.
- Since:
- 4.5.0-M2
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Nested Class Summary
Nested ClassesModifier and TypeInterfaceDescriptionstatic interfaceRepresents an operation that accepts an<index, count>pair. -
Method Summary
Modifier and TypeMethodDescriptionstatic CellExtractorfrom(IndexExtractor indexExtractor) Creates a CellExtractor from an IndexExtractor.booleanprocessCells(CellExtractor.CellPredicate consumer) Performs the given action for eachcellwhere the cell count is non-zero.default booleanprocessIndices(IntPredicate predicate) The default implementation returns distinct and ordered indices for all cells with a non-zero count.default IndexExtractorCreates an IndexExtractor comprising the unique indices for this extractor.Methods inherited from interface org.apache.commons.collections4.bloomfilter.IndexExtractor
asIndexArray
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Method Details
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from
Creates a CellExtractor from an IndexExtractor.Note the following properties:
- Each index returned from the IndexExtractor is assumed to have a cell value of 1.
- The CellExtractor aggregates duplicate indices from the IndexExtractor.
A CellExtractor that outputs the mapping [(1,2),(2,3),(3,1)] can be created from many combinations of indices including:
[1, 1, 2, 2, 2, 3] [1, 3, 1, 2, 2, 2] [3, 2, 1, 2, 1, 2] ...
- Parameters:
indexExtractor- An index indexExtractor.- Returns:
- A CellExtractor with the same indices as the IndexExtractor.
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processCells
Performs the given action for eachcellwhere the cell count is non-zero.Some Bloom filter implementations use a count rather than a bit flag. The term
Cellis used to refer to these counts.Any exceptions thrown by the action are relayed to the caller. The consumer is applied to each cell. If the consumer returns
falsethe execution is stopped,falseis returned, and no further pairs are processed.- Parameters:
consumer- the action to be performed for each non-zero cell.- Returns:
trueif all cells return true from consumer,falseotherwise.- Throws:
NullPointerException- if the specified consumer is null
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processIndices
The default implementation returns distinct and ordered indices for all cells with a non-zero count.- Specified by:
processIndicesin interfaceIndexExtractor- Parameters:
predicate- the action to be performed for each non-zero bit index.- Returns:
trueif all indexes return true from consumer,falseotherwise.
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uniqueIndices
Description copied from interface:IndexExtractorCreates an IndexExtractor comprising the unique indices for this extractor.By default creates a new extractor with some overhead to remove duplicates. IndexExtractors that return unique indices by default should override this to return
this.The default implementation will filter the indices from this instance and return them in ascending order.
- Specified by:
uniqueIndicesin interfaceIndexExtractor- Returns:
- the IndexExtractor of unique values.
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