Class Int2ObjectHashMap<V>

java.lang.Object
org.agrona.collections.Int2ObjectHashMap<V>
Type Parameters:
V - type of values stored in the Map
All Implemented Interfaces:
Map<Integer,V>
Direct Known Subclasses:
Int2NullableObjectHashMap

public class Int2ObjectHashMap<V> extends Object implements Map<Integer,V>
Map implementation specialised for int keys using open addressing and linear probing for cache efficient access.
  • Field Details

  • Constructor Details

    • Int2ObjectHashMap

      public Int2ObjectHashMap()
      Constructs map with MIN_CAPACITY, Hashing.DEFAULT_LOAD_FACTOR and enables caching of iterators.
    • Int2ObjectHashMap

      public Int2ObjectHashMap(int initialCapacity, float loadFactor)
      Constructs map with given initial capacity and load factory and enables caching of iterators.
      Parameters:
      initialCapacity - for the backing array.
      loadFactor - limit for resizing on puts.
    • Int2ObjectHashMap

      public Int2ObjectHashMap(int initialCapacity, float loadFactor, boolean shouldAvoidAllocation)
      Construct a new map allowing a configuration for initial capacity and load factor.
      Parameters:
      initialCapacity - for the backing array.
      loadFactor - limit for resizing on puts.
      shouldAvoidAllocation - should allocation be avoided by caching iterators and map entries.
    • Int2ObjectHashMap

      public Int2ObjectHashMap(Int2ObjectHashMap<V> mapToCopy)
      Copy construct a new map from an existing one.
      Parameters:
      mapToCopy - for construction.
  • Method Details

    • loadFactor

      public float loadFactor()
      Get the load factor beyond which the map will increase size.
      Returns:
      load factor for when the map should increase size.
    • capacity

      public int capacity()
      Get the total capacity for the map to which the load factor will be a fraction of.
      Returns:
      the total capacity for the map.
    • resizeThreshold

      public int resizeThreshold()
      Get the actual threshold which when reached the map will resize. This is a function of the current capacity and load factor.
      Returns:
      the threshold when the map will resize.
    • size

      public int size()
      Specified by:
      size in interface Map<Integer,V>
    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface Map<Integer,V>
    • forEach

      public void forEach(BiConsumer<? super Integer,? super V> action)
      Specified by:
      forEach in interface Map<Integer,V>
    • intForEach

      @Deprecated public void intForEach(IntObjConsumer<V> consumer)
      Deprecated.
      Parameters:
      consumer - a callback called for each key/value pair in the map.
      See Also:
    • forEachInt

      public void forEachInt(IntObjConsumer<V> consumer)
      Primitive specialised implementation of Map.forEach(BiConsumer).

      NB: Renamed from forEach to avoid overloading on parameter types of lambda expression, which doesn't play well with type inference in lambda expressions.

      Parameters:
      consumer - a callback called for each key/value pair in the map.
    • containsKey

      public boolean containsKey(Object key)
      Specified by:
      containsKey in interface Map<Integer,V>
    • containsKey

      public boolean containsKey(int key)
      Overloaded version of Map.containsKey(Object) that takes a primitive int key.
      Parameters:
      key - for indexing the Map.
      Returns:
      true if the key is found otherwise false.
    • containsValue

      public boolean containsValue(Object value)
      Specified by:
      containsValue in interface Map<Integer,V>
    • get

      public V get(Object key)
      Specified by:
      get in interface Map<Integer,V>
    • get

      public V get(int key)
      Overloaded version of Map.get(Object) that takes a primitive int key.
      Parameters:
      key - for indexing the Map.
      Returns:
      the value if found otherwise null.
    • getOrDefault

      public V getOrDefault(int key, V defaultValue)
      Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.
      Parameters:
      key - whose associated value is to be returned.
      defaultValue - the default mapping of the key.
      Returns:
      the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.
    • getMapped

      protected V getMapped(int key)
      Get mapped value without boxing the key.
      Parameters:
      key - to get value by.
      Returns:
      mapped value or null.
    • computeIfAbsent

      public V computeIfAbsent(Integer key, Function<? super Integer,? extends V> mappingFunction)
      Specified by:
      computeIfAbsent in interface Map<Integer,V>
    • computeIfAbsent

      public V computeIfAbsent(int key, IntFunction<? extends V> mappingFunction)
      Get a value for a given key, or if it does not exist then default the value via a IntFunction and put it in the map.

      Primitive specialized version of Map.computeIfAbsent(Object, Function).

      Parameters:
      key - to search on.
      mappingFunction - to provide a value if the get returns null.
      Returns:
      the value if found otherwise the default.
    • computeIfPresent

      public V computeIfPresent(Integer key, BiFunction<? super Integer,? super V,? extends V> remappingFunction)
      Specified by:
      computeIfPresent in interface Map<Integer,V>
    • computeIfPresent

      public V computeIfPresent(int key, IntObjectToObjectFunction<? super V,? extends V> remappingFunction)
      If the value for the specified key is present and non-null, attempts to compute a new mapping given the key and its current mapped value.

      If the function returns null, the mapping is removed.

      Primitive specialized version of Map.computeIfPresent(Object, BiFunction).

      Parameters:
      key - to search on.
      remappingFunction - to provide a value if the get returns missingValue.
      Returns:
      the new value associated with the specified key, or null if none.
    • compute

      public V compute(Integer key, BiFunction<? super Integer,? super V,? extends V> remappingFunction)
      Specified by:
      compute in interface Map<Integer,V>
    • compute

      public V compute(int key, IntObjectToObjectFunction<? super V,? extends V> remappingFunction)
      Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).

      If the function returns null, the mapping is removed (or remains absent if initially absent).

      Primitive specialized version of Map.compute(Object, BiFunction).

      Parameters:
      key - to search on.
      remappingFunction - to provide a value if the get returns missingValue.
      Returns:
      the new value associated with the specified key, or null if none.
    • merge

      public V merge(Integer key, V value, BiFunction<? super V,? super V,? extends V> remappingFunction)
      Specified by:
      merge in interface Map<Integer,V>
    • merge

      public V merge(int key, V value, BiFunction<? super V,? super V,? extends V> remappingFunction)
      Primitive specialised version of Map.merge(Object, Object, BiFunction).
      Parameters:
      key - with which the resulting value is to be associated.
      value - the non-null value to be merged with the existing value associated with the key or, if no existing value or a null value is associated with the key, to be associated with the key.
      remappingFunction - the function to recompute a value if present.
      Returns:
      the new value associated with the specified key, or null if no value is associated with the key.
    • put

      public V put(Integer key, V value)
      Specified by:
      put in interface Map<Integer,V>
    • put

      public V put(int key, V value)
      Overloaded version of Map.put(Object, Object) that takes a primitive int key.
      Parameters:
      key - for indexing the Map.
      value - to be inserted in the Map.
      Returns:
      the previous value if found otherwise null.
    • remove

      public V remove(Object key)
      Specified by:
      remove in interface Map<Integer,V>
    • remove

      public V remove(int key)
      Overloaded version of Map.remove(Object) that takes a primitive int key.
      Parameters:
      key - for indexing the Map.
      Returns:
      the value if found otherwise null.
    • remove

      public boolean remove(Object key, Object value)
      Specified by:
      remove in interface Map<Integer,V>
    • remove

      public boolean remove(int key, V value)
      Primitive specialised version of Map.remove(Object, Object).
      Parameters:
      key - with which the specified value is associated.
      value - expected to be associated with the specified key.
      Returns:
      true if the value was removed.
    • clear

      public void clear()
      Specified by:
      clear in interface Map<Integer,V>
    • compact

      public void compact()
      Compact the Map backing arrays by rehashing with a capacity just larger than current size and giving consideration to the load factor.
    • putAll

      public void putAll(Map<? extends Integer,? extends V> map)
      Specified by:
      putAll in interface Map<Integer,V>
    • putAll

      public void putAll(Int2ObjectHashMap<? extends V> map)
      Put all values from the given map into this one without allocation.
      Parameters:
      map - whose value are to be added.
    • putIfAbsent

      public V putIfAbsent(int key, V value)
      Primitive specialised version of Map.putIfAbsent(Object, Object).
      Parameters:
      key - with which the specified value is to be associated.
      value - to be associated with the specified key.
      Returns:
      the previous value associated with the specified key, or null if there was no mapping for the key.
    • keySet

      public Int2ObjectHashMap<V>.KeySet keySet()
      Specified by:
      keySet in interface Map<Integer,V>
    • values

      Specified by:
      values in interface Map<Integer,V>
    • entrySet

      public Int2ObjectHashMap<V>.EntrySet entrySet()
      Specified by:
      entrySet in interface Map<Integer,V>
    • toString

      public String toString()
      Overrides:
      toString in class Object
    • equals

      public boolean equals(Object o)
      Specified by:
      equals in interface Map<Integer,V>
      Overrides:
      equals in class Object
    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface Map<Integer,V>
      Overrides:
      hashCode in class Object
    • mapNullValue

      protected Object mapNullValue(Object value)
      Interceptor for masking null values.
      Parameters:
      value - value to mask.
      Returns:
      masked value.
    • unmapNullValue

      protected V unmapNullValue(Object value)
      Interceptor for unmasking null values.
      Parameters:
      value - value to unmask.
      Returns:
      unmasked value.
    • replace

      public V replace(int key, V value)
      Primitive specialised version of Map.replace(Object, Object).
      Parameters:
      key - key with which the specified value is associated.
      value - value to be associated with the specified key.
      Returns:
      the previous value associated with the specified key, or null if there was no mapping for the key.
    • replace

      public boolean replace(int key, V oldValue, V newValue)
      Primitive specialised version of Map.replace(Object, Object, Object).
      Parameters:
      key - key with which the specified value is associated.
      oldValue - value expected to be associated with the specified key.
      newValue - value to be associated with the specified key.
      Returns:
      true if the value was replaced.
    • replaceAll

      public void replaceAll(BiFunction<? super Integer,? super V,? extends V> function)
      Specified by:
      replaceAll in interface Map<Integer,V>
    • replaceAllInt

      public void replaceAllInt(IntObjectToObjectFunction<? super V,? extends V> function)
      Primitive specialised version of Map.replaceAll(BiFunction).

      NB: Renamed from replaceAll to avoid overloading on parameter types of lambda expression, which doesn't play well with type inference in lambda expressions.

      Parameters:
      function - the function to apply to each entry.
    • increaseCapacity

      private void increaseCapacity()
    • rehash

      private void rehash(int newCapacity)
    • compactChain

      private void compactChain(int deleteIndex)