org.apache.lucene.util

Class SparseFixedBitSet

  • All Implemented Interfaces:
    Accountable, Bits, MutableBits


    public class SparseFixedBitSet
    extends BitSet
    implements Bits, Accountable
    A bit set that only stores longs that have at least one bit which is set. The way it works is that the space of bits is divided into blocks of 4096 bits, which is 64 longs. Then for each block, we have:
    • a long[] which stores the non-zero longs for that block
    • a long so that bit i being set means that the i-th long of the block is non-null, and its offset in the array of longs is the number of one bits on the right of the i-th bit.
    • Method Detail

      • length

        public int length()
        Description copied from interface: Bits
        Returns the number of bits in this set
        Specified by:
        length in interface Bits
      • cardinality

        public int cardinality()
        Description copied from class: BitSet
        Return the number of bits that are set. NOTE: this method is likely to run in linear time
        Specified by:
        cardinality in class BitSet
      • approximateCardinality

        public int approximateCardinality()
        Description copied from class: BitSet
        Return an approximation of the cardinality of this set. Some implementations may trade accuracy for speed if they have the ability to estimate the cardinality of the set without iterating over all the data. The default implementation returns BitSet.cardinality().
        Overrides:
        approximateCardinality in class BitSet
      • get

        public boolean get(int i)
        Description copied from interface: Bits
        Returns the value of the bit with the specified index.
        Specified by:
        get in interface Bits
        Parameters:
        i - index, should be non-negative and < Bits.length(). The result of passing negative or out of bounds values is undefined by this interface, just don't do it!
        Returns:
        true if the bit is set, false otherwise.
      • set

        public void set(int i)
        Set the bit at index i.
        Specified by:
        set in class BitSet
      • clear

        public void clear(int i)
        Clear the bit at index i.
        Specified by:
        clear in interface MutableBits
        Parameters:
        i - index, should be non-negative and < Bits.length(). The result of passing negative or out of bounds values is undefined by this interface, just don't do it!
      • clear

        public void clear(int from,
                          int to)
        Description copied from class: BitSet
        Clears a range of bits.
        Specified by:
        clear in class BitSet
        Parameters:
        from - lower index
        to - one-past the last bit to clear
      • prevSetBit

        public int prevSetBit(int i)
        Description copied from class: BitSet
        Returns the index of the last set bit before or on the index specified. -1 is returned if there are no more set bits.
        Specified by:
        prevSetBit in class BitSet
      • or

        public void or(DocIdSetIterator it)
                throws IOException
        Description copied from class: BitSet
        Does in-place OR of the bits provided by the iterator. The state of the iterator after this operation terminates is undefined.
        Overrides:
        or in class BitSet
        Throws:
        IOException