Package org.apache.lucene.util.hppc

Class IntIntHashMap

java.lang.Object
org.apache.lucene.util.hppc.IntIntHashMap
All Implemented Interfaces:
Cloneable, Iterable<IntIntHashMap.IntIntCursor>
public class IntIntHashMap extends Object implements Iterable<IntIntHashMap.IntIntCursor>, Cloneable
A hash map of int to int, implemented using open addressing with linear probing for collision resolution.

Mostly forked and trimmed from com.carrotsearch.hppc.IntIntHashMap

github: https://github.com/carrotsearch/hppc release 0.9.0

  • Field Details

    • DEFAULT_EXPECTED_ELEMENTS

      public static final int DEFAULT_EXPECTED_ELEMENTS
      See Also:

    • DEFAULT_LOAD_FACTOR

      public static final float DEFAULT_LOAD_FACTOR
      See Also:

    • MIN_LOAD_FACTOR

      public static final float MIN_LOAD_FACTOR
      Minimal sane load factor (99 empty slots per 100).
      See Also:

    • MAX_LOAD_FACTOR

      public static final float MAX_LOAD_FACTOR
      Maximum sane load factor (1 empty slot per 100).
      See Also:

    • MIN_HASH_ARRAY_LENGTH

      public static final int MIN_HASH_ARRAY_LENGTH
      Minimum hash buffer size.
      See Also:

    • MAX_HASH_ARRAY_LENGTH

      public static final int MAX_HASH_ARRAY_LENGTH
      Maximum array size for hash containers (power-of-two and still allocable in Java, not a negative int).
      See Also:

    • keys

      public int[] keys
      The array holding keys.

    • values

      public int[] values
      The array holding values.

    • assigned

      protected int assigned
      The number of stored keys (assigned key slots), excluding the special "empty" key, if any (use size() instead).
      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

    • IntIntHashMap

      public IntIntHashMap()
      New instance with sane defaults.

    • IntIntHashMap

      public IntIntHashMap(int expectedElements)
      New instance with sane defaults.
      Parameters:
      expectedElements - The expected number of elements guaranteed not to cause buffer expansion (inclusive).

    • IntIntHashMap

      public IntIntHashMap(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).

    • IntIntHashMap

      public IntIntHashMap(Iterable<? extends IntIntHashMap.IntIntCursor> container)
      Create a hash map from all key-value pairs of another container.

  • Method Details

    • put

      public int put(int key, int value)

    • putAll

      public int putAll(Iterable<? extends IntIntHashMap.IntIntCursor> iterable)

    • putIfAbsent

      public boolean putIfAbsent(int key, int value)
      Trove-inspired API method. An equivalent of the following code: 
       if (!map.containsKey(key)) map.put(value);
      Parameters:
      key - The key of the value to check.
      value - The value to put if key does not exist.
      Returns:
      true if key did not exist and value was placed in the map.

    • putOrAdd

      public int putOrAdd(int key, int putValue, int incrementValue)
      If key exists, putValue is inserted into the map, otherwise any existing value is incremented by additionValue.
      Parameters:
      key - The key of the value to adjust.
      putValue - The value to put if key does not exist.
      incrementValue - The value to add to the existing value if key exists.
      Returns:
      Returns the current value associated with key (after changes).

    • addTo

      public int addTo(int key, int incrementValue)
      Adds incrementValue to any existing value for the given key or inserts incrementValue if key did not previously exist.
      Parameters:
      key - The key of the value to adjust.
      incrementValue - The value to put or add to the existing value if key exists.
      Returns:
      Returns the current value associated with key (after changes).

    • remove

      public int remove(int key)

    • get

      public int get(int key)

    • getOrDefault

      public int getOrDefault(int key, int defaultValue)

    • containsKey

      public boolean containsKey(int key)

    • indexOf

      public int indexOf(int key)

    • indexExists

      public boolean indexExists(int index)

    • indexGet

      public int indexGet(int index)

    • indexReplace

      public int indexReplace(int index, int newValue)

    • indexInsert

      public void indexInsert(int index, int key, int value)

    • indexRemove

      public int indexRemove(int index)

    • clear

      public void clear()

    • release

      public void release()

    • size

      public int size()

    • isEmpty

      public boolean isEmpty()

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

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

    • equalElements

      protected boolean equalElements(IntIntHashMap other)
      Return true if all keys of some other container exist in this container.

    • ensureCapacity

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

    • 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.

    • iterator

      public Iterator<IntIntHashMap.IntIntCursor> iterator()
      Specified by:
      iterator in interface Iterable<IntIntHashMap.IntIntCursor>

    • keys

      public IntIntHashMap.KeysContainer keys()
      Returns a specialized view of the keys of this associated container.

    • values

      public IntIntHashMap.IntContainer values()
      Returns:
      Returns a container with all values stored in this map.

    • clone

      public IntIntHashMap clone()
      Overrides:
      clone in class Object

    • toString

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

    • from

      public static IntIntHashMap from(int[] keys, int[] values)
      Creates a hash map from two index-aligned arrays of key-value pairs.

    • 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.

    • 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, int[] fromValues)
      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, int pendingValue)
      This method is invoked when there is a new key/ value pair to be inserted into the buffers 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 and values allocated to (and including) slot.