Package org.kingdoms.utils.internal.integer

Class IntHashSet

java.lang.Object
org.kingdoms.utils.internal.integer.IntHashSet
All Implemented Interfaces:
Iterable<IntHashSet.IntCursor>
public class IntHashSet extends Object implements Iterable<IntHashSet.IntCursor>
A hash set of ints, implemented using using open addressing with linear probing for collision resolution.
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    protected final class 
    IntHashSet.EntryIterator
    An iterator implementation for iterator().
    static final class 
    IntHashSet.IntCursor
     

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected int
    assigned
    The number of stored keys (assigned key slots), excluding the special "empty" key, if any.
    protected boolean
    hasEmptyKey
    Special treatment for the "empty slot" key marker.
    protected int
    iterationSeed
    Seed used to ensure the hash iteration order is different from an iteration to another.
    int[]
    keys
    The hash array holding keys.
    protected double
    loadFactor
    The load factor for keys.
    protected int
    mask
    Mask for slot scans in keys.
    protected int
    resizeAt
    Expand (rehash) keys when assigned hits this value.

  • Constructor Summary

    Constructors
    Constructor
    Description
    IntHashSet()
    New instance with sane defaults.
    IntHashSet(int expectedElements)
    New instance with sane defaults.
    IntHashSet(int expectedElements, double loadFactor)
    New instance with the provided defaults.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    add(int key)
     
    protected void
    allocateBuffers(int arraySize)
    Allocate new internal buffers.
    protected void
    allocateThenInsertThenRehash(int slot, int pendingKey)
    This method is invoked when there is a new key to be inserted into the buffer but there is not enough empty slots to do so.
    void
    clear()
     
    boolean
    contains(int key)
     
    void
    ensureCapacity(int expectedElements)
    Ensure this container can hold at least the given number of elements without resizing its buffers.
    boolean
    equals(Object obj)
     
    int
    hashCode()
     
    protected int
    hashKey(int key)
    Returns a hash code for the given key.
    int
    indexOf(int key)
    Returns a logical "index" of a given key that can be used to speed up follow-up logic in certain scenarios (conditional logic).
    boolean
    isEmpty()
     
    Iterator<IntHashSet.IntCursor>
    iterator()
     
    protected int
    nextIterationSeed()
    Provides the next iteration seed used to build the iteration starting slot and offset increment.
    protected void
    rehash(int[] fromKeys)
    Rehash from old buffers to new buffers.
    void
    release()
     
    boolean
    remove(int key)
     
    protected void
    shiftConflictingKeys(int gapSlot)
    Shift all the slot-conflicting keys allocated to (and including) slot.
    int
    size()
     
    int[]
    toArray()
     
    String
    toString()
    Convert the contents of this container to a human-friendly string.
    protected double
    verifyLoadFactor(double loadFactor)
    Validate load factor range and return it.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    Methods inherited from interface java.lang.Iterable

    forEach, spliterator

  • Field Details

    • keys

      public int[] keys
      The hash array holding keys.

    • assigned

      protected int assigned
      The number of stored keys (assigned key slots), excluding the special "empty" key, if any.
      See Also:

    • mask

      protected int mask
      Mask for slot scans in keys.

    • resizeAt

      protected int resizeAt
      Expand (rehash) keys when assigned hits this value.

    • hasEmptyKey

      protected boolean hasEmptyKey
      Special treatment for the "empty slot" key marker.

    • loadFactor

      protected double loadFactor
      The load factor for keys.

    • iterationSeed

      protected int iterationSeed
      Seed used to ensure the hash iteration order is different from an iteration to another.

  • Constructor Details

    • IntHashSet

      public IntHashSet()
      New instance with sane defaults.
      See Also:

    • IntHashSet

      public IntHashSet(int expectedElements)
      New instance with sane defaults.
      See Also:

    • IntHashSet

      public IntHashSet(int expectedElements, double loadFactor)
      New instance with the provided defaults.
      Parameters:
      expectedElements - The expected number of elements guaranteed not to cause a rehash (inclusive).
      loadFactor - The load factor for internal buffers. Insane load factors (zero, full capacity) are rejected by verifyLoadFactor(double).

  • Method Details

    • toString

      public String toString()
      Convert the contents of this container to a human-friendly string.
      Overrides:
      toString in class Object

    • add

      public boolean add(int key)

    • toArray

      public int[] toArray()

    • remove

      public boolean remove(int key)

    • contains

      public boolean contains(int key)

    • clear

      public void clear()

    • release

      public void release()

    • isEmpty

      public boolean isEmpty()

    • ensureCapacity

      public void ensureCapacity(int expectedElements)
      Ensure this container can hold at least the given number of elements without resizing its buffers.
      Parameters:
      expectedElements - The total number of elements, inclusive.

    • size

      public int size()

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • iterator

      public Iterator<IntHashSet.IntCursor> iterator()
      Specified by:
      iterator in interface Iterable<IntHashSet.IntCursor>

    • nextIterationSeed

      protected int nextIterationSeed()
      Provides the next iteration seed used to build the iteration starting slot and offset increment. This method does not need to be synchronized, what matters is that each thread gets a sequence of varying seeds.

    • hashKey

      protected int hashKey(int key)
      Returns a hash code for the given key.

      The output from this function should evenly distribute keys across the entire integer range.

    • indexOf

      public int indexOf(int key)
      Returns a logical "index" of a given key that can be used to speed up follow-up logic in certain scenarios (conditional logic).

      The semantics of "indexes" are not strictly defined. Indexes may (and typically won't be) contiguous.

      The index is valid only between modifications (it will not be affected by read-only operations)

      Parameters:
      key - The key to locate in the set.
      Returns:
      A non-negative value of the logical "index" of the key in the set or a negative value if the key did not exist.

    • verifyLoadFactor

      protected double verifyLoadFactor(double loadFactor)
      Validate load factor range and return it. Override and suppress if you need insane load factors.

    • rehash

      protected void rehash(int[] fromKeys)
      Rehash from old buffers to new buffers.

    • allocateBuffers

      protected void allocateBuffers(int arraySize)
      Allocate new internal buffers. This method attempts to allocate and assign internal buffers atomically (either allocations succeed or not).

    • allocateThenInsertThenRehash

      protected void allocateThenInsertThenRehash(int slot, int pendingKey)
      This method is invoked when there is a new key to be inserted into the buffer but there is not enough empty slots to do so.

      New buffers are allocated. If this succeeds, we know we can proceed with rehashing so we assign the pending element to the previous buffer (possibly violating the invariant of having at least one empty slot) and rehash all keys, substituting new buffers at the end.

    • shiftConflictingKeys

      protected void shiftConflictingKeys(int gapSlot)
      Shift all the slot-conflicting keys allocated to (and including) slot.