Package org.apache.lucene.util

Class LongBitSet

java.lang.Object
org.apache.lucene.util.LongBitSet
All Implemented Interfaces:
Accountable
public final class LongBitSet extends Object implements Accountable
BitSet of fixed length (numBits), backed by accessible (getBits()) long[], accessed with a long index. Use it only if you intend to store more than 2.1B bits, otherwise you should use FixedBitSet.
NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final long
    MAX_NUM_BITS
    The maximum numBits supported.

    Fields inherited from interface org.apache.lucene.util.Accountable

    NULL_ACCOUNTABLE

  • Constructor Summary

    Constructors
    Constructor
    Description
    LongBitSet(long numBits)
    Creates a new LongBitSet.
    LongBitSet(long[] storedBits, long numBits)
    Creates a new LongBitSet using the provided long[] array as backing store.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    and(LongBitSet other)
    this = this AND other
    void
    andNot(LongBitSet other)
    this = this AND NOT other
    static int
    bits2words(long numBits)
    Returns the number of 64 bit words it would take to hold numBits
    long
    cardinality()
    Returns number of set bits.
    void
    clear(long index)
     
    void
    clear(long startIndex, long endIndex)
    Clears a range of bits.
    LongBitSet
    clone()
     
    static LongBitSet
    ensureCapacity(LongBitSet bits, long numBits)
    If the given LongBitSet is large enough to hold numBits+1, returns the given bits, otherwise returns a new LongBitSet which can hold the requested number of bits.
    boolean
    equals(Object o)
    returns true if both sets have the same bits set
    void
    flip(long index)
    Flip the bit at the provided index.
    void
    flip(long startIndex, long endIndex)
    Flips a range of bits
    boolean
    get(long index)
     
    boolean
    getAndClear(long index)
     
    boolean
    getAndSet(long index)
     
    long[]
    getBits()
    Expert.
    int
    hashCode()
     
    boolean
    intersects(LongBitSet other)
    returns true if the sets have any elements in common
    long
    length()
    Returns the number of bits stored in this bitset.
    long
    nextSetBit(long index)
    Returns the index of the first set bit starting at the index specified.
    void
    or(LongBitSet other)
    this = this OR other
    long
    prevSetBit(long index)
    Returns the index of the last set bit before or on the index specified.
    long
    ramBytesUsed()
    Return the memory usage of this object in bytes.
    boolean
    scanIsEmpty()
    Scans the backing store to check if all bits are clear.
    void
    set(long index)
     
    void
    set(long startIndex, long endIndex)
    Sets a range of bits
    void
    xor(LongBitSet other)
    this = this XOR other

    Methods inherited from class java.lang.Object

    finalize, getClass, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface org.apache.lucene.util.Accountable

    getChildResources

  • Field Details

    • MAX_NUM_BITS

      public static final long MAX_NUM_BITS
      The maximum numBits supported.

  • Constructor Details

    • LongBitSet

      public LongBitSet(long numBits)
      Creates a new LongBitSet. The internally allocated long array will be exactly the size needed to accommodate the numBits specified.
      Parameters:
      numBits - the number of bits needed

    • LongBitSet

      public LongBitSet(long[] storedBits, long numBits)
      Creates a new LongBitSet using the provided long[] array as backing store. The storedBits array must be large enough to accommodate the numBits specified, but may be larger. In that case the 'extra' or 'ghost' bits must be clear (or they may provoke spurious side-effects)
      Parameters:
      storedBits - the array to use as backing store
      numBits - the number of bits actually needed

  • Method Details

    • ensureCapacity

      public static LongBitSet ensureCapacity(LongBitSet bits, long numBits)
      If the given LongBitSet is large enough to hold numBits+1, returns the given bits, otherwise returns a new LongBitSet which can hold the requested number of bits.

      NOTE: the returned bitset reuses the underlying long[] of the given bits if possible. Also, calling length() on the returned bits may return a value greater than numBits.

    • bits2words

      public static int bits2words(long numBits)
      Returns the number of 64 bit words it would take to hold numBits

    • length

      public long length()
      Returns the number of bits stored in this bitset.

    • getBits

      public long[] getBits()
      Expert.

    • cardinality

      public long cardinality()
      Returns number of set bits. NOTE: this visits every long in the backing bits array, and the result is not internally cached!

    • get

      public boolean get(long index)

    • set

      public void set(long index)

    • getAndSet

      public boolean getAndSet(long index)

    • clear

      public void clear(long index)

    • getAndClear

      public boolean getAndClear(long index)

    • nextSetBit

      public long nextSetBit(long index)
      Returns the index of the first set bit starting at the index specified. -1 is returned if there are no more set bits.

    • prevSetBit

      public long prevSetBit(long index)
      Returns the index of the last set bit before or on the index specified. -1 is returned if there are no more set bits.

    • or

      public void or(LongBitSet other)
      this = this OR other

    • xor

      public void xor(LongBitSet other)
      this = this XOR other

    • intersects

      public boolean intersects(LongBitSet other)
      returns true if the sets have any elements in common

    • and

      public void and(LongBitSet other)
      this = this AND other

    • andNot

      public void andNot(LongBitSet other)
      this = this AND NOT other

    • scanIsEmpty

      public boolean scanIsEmpty()
      Scans the backing store to check if all bits are clear. The method is deliberately not called "isEmpty" to emphasize it is not low cost (as isEmpty usually is).
      Returns:
      true if all bits are clear.

    • flip

      public void flip(long startIndex, long endIndex)
      Flips a range of bits
      Parameters:
      startIndex - lower index
      endIndex - one-past the last bit to flip

    • flip

      public void flip(long index)
      Flip the bit at the provided index.

    • set

      public void set(long startIndex, long endIndex)
      Sets a range of bits
      Parameters:
      startIndex - lower index
      endIndex - one-past the last bit to set

    • clear

      public void clear(long startIndex, long endIndex)
      Clears a range of bits.
      Parameters:
      startIndex - lower index
      endIndex - one-past the last bit to clear

    • clone

      public LongBitSet clone()
      Overrides:
      clone in class Object

    • equals

      public boolean equals(Object o)
      returns true if both sets have the same bits set
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • ramBytesUsed

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