Package org.apache.lucene.util

Class SparseFixedBitSet

java.lang.Object
org.apache.lucene.util.BitSet
org.apache.lucene.util.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 Details

    • SparseFixedBitSet

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

  • Method Details

    • 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.

    • toString

      public String toString()
      Overrides:
      toString in class Object