Package org.apache.commons.collections4.bloomfilter

Interface IndexProducer

All Known Subinterfaces:

BloomFilter, CellProducer, CountingBloomFilter

All Known Implementing Classes:

ArrayCountingBloomFilter, LayeredBloomFilter, SimpleBloomFilter, SparseBloomFilter, WrappedBloomFilter

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface IndexProducer

An object that produces indices of a Bloom filter.

The default implementation of asIndexArray is slow. Implementers should reimplement the method where possible.

Since:

4.5

Method Summary

Modifier and Type	Method	Description
default int[]	asIndexArray()	Return a copy of the IndexProducer data as an int array.
boolean	forEachIndex(IntPredicate predicate)	Each index is passed to the predicate.
static IndexProducer	fromBitMapProducer(BitMapProducer producer)	Creates an IndexProducer from a BitMapProducer.
static IndexProducer	fromIndexArray(int... values)	Creates an IndexProducer from an array of integers.
default IndexProducer	uniqueIndices()	Creates an IndexProducer comprising the unique indices for this producer.

Method Details

fromBitMapProducer

static IndexProducer fromBitMapProducer(BitMapProducer producer)

Creates an IndexProducer from a BitMapProducer.

Parameters:

producer - the BitMapProducer

Returns:

a new IndexProducer.

fromIndexArray

static IndexProducer fromIndexArray(int... values)

Creates an IndexProducer from an array of integers.

Parameters:

values - the index values

Returns:

an IndexProducer that uses the values.

asIndexArray

default int[] asIndexArray()

Return a copy of the IndexProducer data as an int array.

Indices ordering and uniqueness is not guaranteed.

The default implementation of this method creates an array and populates it. Implementations that have access to an index array should consider returning a copy of that array if possible.

Returns:

An int array of the data.

forEachIndex

boolean forEachIndex(IntPredicate predicate)

Each index is passed to the predicate. The predicate is applied to each index value, if the predicate returns false the execution is stopped, false is returned, and no further indices are processed.

Any exceptions thrown by the action are relayed to the caller.

Indices ordering and uniqueness is not guaranteed.

Parameters:

predicate - the action to be performed for each non-zero bit index.

Returns:

true if all indexes return true from consumer, false otherwise.

Throws:

NullPointerException - if the specified action is null

uniqueIndices

default IndexProducer uniqueIndices()

Creates an IndexProducer comprising the unique indices for this producer.

By default creates a new producer with some overhead to remove duplicates. IndexProducers 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.

Returns:

the IndexProducer of unique values.

Throws:

IndexOutOfBoundsException - if any index is less than zero.