Package org.apache.commons.collections4.bloomfilter

Interface BitMapProducer

All Known Subinterfaces:
BloomFilter, 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 BitMapProducer
Produces bit map longs for a Bloom filter. Each bit map is a little-endian long value representing a block of bits of in a filter.

The returned array will have length ceil(m / 64) where m is the number of bits in the filter and ceil is the ceiling function. Bits 0-63 are in the first long. A value of 1 at a bit position indicates the bit index is enabled.

The default implementations of the makePredicate() and asBitMapArray methods are slow and should be reimplemented in the implementing classes where possible.

Since:
4.5

  • Method Details

    • fromBitMapArray

      static BitMapProducer fromBitMapArray(long... bitMaps)
      Creates a BitMapProducer from an array of Long.
      Parameters:
      bitMaps - the bit maps to return.
      Returns:
      a BitMapProducer.

    • fromIndexProducer

      static BitMapProducer fromIndexProducer(IndexProducer producer, int numberOfBits)
      Creates a BitMapProducer from an IndexProducer.
      Parameters:
      producer - the IndexProducer that specifies the indexes of the bits to enable.
      numberOfBits - the number of bits in the Bloom filter.
      Returns:
      A BitMapProducer that produces the bit maps equivalent of the Indices from the producer.

    • asBitMapArray

      default long[] asBitMapArray()
      Return a copy of the BitMapProducer data as a bit map array.

      The default implementation of this method is slow. It is recommended that implementing classes reimplement this method.

      Returns:
      An array of bit map data.

    • forEachBitMap

      boolean forEachBitMap(LongPredicate predicate)
      Each bit map is passed to the predicate in order. The predicate is applied to each bit map value, if the predicate returns false the execution is stopped, false is returned, and no further bit maps are processed.

      If the producer is empty this method will return true.

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

      Parameters:
      predicate - the function to execute
      Returns:
      true if all bit maps returned true, false otherwise.
      Throws:
      NullPointerException - if the specified consumer is null

    • forEachBitMapPair

      default boolean forEachBitMapPair(BitMapProducer other, LongBiPredicate func)
      Applies the func to each bit map pair in order. Will apply all of the bit maps from the other BitMapProducer to this producer. If this producer does not have as many bit maps it will provide 0 (zero) for all excess calls to the LongBiPredicate.

      The default implementation of this method uses asBitMapArray(). It is recommended that implementations of BitMapProducer that have local arrays reimplement this method.

      Parameters:
      other - The other BitMapProducer that provides the y values in the (x,y) pair.
      func - The function to apply.
      Returns:
      A LongPredicate that tests this BitMapProducers bitmap values in order.