Class IntIntHashMap

  • All Implemented Interfaces:
    java.lang.Cloneable, java.lang.Iterable<IntIntHashMap.IntIntCursor>, Accountable

    public class IntIntHashMap
    extends java.lang.Object
    implements java.lang.Iterable<IntIntHashMap.IntIntCursor>, Accountable, java.lang.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 0.10.0

    • 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 (use size() instead).
      private static long BASE_RAM_BYTES_USED  
      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 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.
      int[] values
      The array holding values.
    • Constructor Summary

      Constructors 
      Constructor Description
      IntIntHashMap()
      New instance with sane defaults.
      IntIntHashMap​(int expectedElements)
      New instance with sane defaults.
      IntIntHashMap​(int expectedElements, double loadFactor)
      New instance with the provided defaults.
      IntIntHashMap​(IntIntHashMap map)
      Create a hash map from all key-value pairs of another map.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      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.
      protected void allocateBuffers​(int arraySize)
      Allocate new internal buffers.
      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.
      void clear()  
      IntIntHashMap clone()  
      boolean containsKey​(int key)  
      void ensureCapacity​(int expectedElements)
      Ensure this container can hold at least the given number of keys (entries) without resizing its buffers.
      protected boolean equalElements​(IntIntHashMap other)
      Return true if all keys of some other container exist in this container.
      boolean equals​(java.lang.Object obj)  
      static IntIntHashMap from​(int[] keys, int[] values)
      Creates a hash map from two index-aligned arrays of key-value pairs.
      int get​(int key)  
      int getOrDefault​(int key, int defaultValue)  
      int hashCode()  
      protected int hashKey​(int key)
      Returns a hash code for the given key.
      boolean indexExists​(int index)  
      int indexGet​(int index)  
      void indexInsert​(int index, int key, int value)  
      int indexOf​(int key)  
      int indexRemove​(int index)  
      int indexReplace​(int index, int newValue)  
      boolean isEmpty()  
      java.util.Iterator<IntIntHashMap.IntIntCursor> iterator()  
      IntIntHashMap.KeysContainer keys()
      Returns a specialized view of the keys of this associated container.
      protected int nextIterationSeed()
      Provides the next iteration seed used to build the iteration starting slot and offset increment.
      int put​(int key, int value)  
      int putAll​(java.lang.Iterable<? extends IntIntHashMap.IntIntCursor> iterable)  
      boolean putIfAbsent​(int key, int value)
      Trove-inspired API method.
      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.
      long ramBytesUsed()
      Return the memory usage of this object in bytes.
      protected void rehash​(int[] fromKeys, int[] fromValues)
      Rehash from old buffers to new buffers.
      void release()  
      int remove​(int key)  
      protected void shiftConflictingKeys​(int gapSlot)
      Shift all the slot-conflicting keys and values allocated to (and including) slot.
      int size()  
      java.lang.String toString()
      Convert the contents of this map to a human-friendly string.
      IntIntHashMap.IntContainer values()  
      protected double verifyLoadFactor​(double loadFactor)
      Validate load factor range and return it.
      • Methods inherited from class java.lang.Object

        finalize, getClass, notify, notifyAll, wait, wait, wait
      • Methods inherited from interface java.lang.Iterable

        forEach, spliterator
    • Field Detail

      • BASE_RAM_BYTES_USED

        private static final long BASE_RAM_BYTES_USED
      • 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:
        size()
      • 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 Detail

      • 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​(IntIntHashMap map)
        Create a hash map from all key-value pairs of another map.
    • Method Detail

      • put

        public int put​(int key,
                       int value)
      • 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 java.lang.Object
      • equals

        public boolean equals​(java.lang.Object obj)
        Overrides:
        equals in class java.lang.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.
      • 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
      • clone

        public IntIntHashMap clone()
        Overrides:
        clone in class java.lang.Object
      • toString

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