Package org.apache.lucene.util

Class SparseFixedBitSet

  • All Implemented Interfaces:
    Accountable, Bits
    public class SparseFixedBitSet
extends BitSet
    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.
    NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

    • Constructor Detail

      • SparseFixedBitSet

        public SparseFixedBitSet​(int length)
        Create a SparseFixedBitSet that can contain bits between 0 included and length excluded.

    • Method Detail

      • clear

        public void clear()
        Description copied from class: BitSet
        Clear all the bits of the set.

        Depending on the implementation, this may be significantly faster than clear(0, length).

        Overrides:
        clear in class BitSet

      • length

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

      • 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().
        Specified by:
        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.
        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.

      • getAndSet

        public boolean getAndSet​(int i)
        Description copied from class: BitSet
        Set the bit at i, returning true if it was previously set.
        Specified by:
        getAndSet in class BitSet

      • 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 class BitSet

      • 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

      • nextSetBit

        public int nextSetBit​(int i)
        Description copied from class: BitSet
        Returns the index of the first set bit starting at the index specified. DocIdSetIterator.NO_MORE_DOCS is returned if there are no more set bits.
        Specified by:
        nextSetBit in class BitSet

      • 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

      • ramBytesUsed

        public long ramBytesUsed()
        Description copied from interface: Accountable
        Return the memory usage of this object in bytes. Negative values are illegal.