org.agrona.collections

Class Object2IntHashMap<K>

java.lang.Object

org.agrona.collections.Object2IntHashMap<K>

Type Parameters:

K - type of keys stored in the Map

All Implemented Interfaces:

java.io.Serializable, java.util.Map<K,java.lang.Integer>

public class Object2IntHashMap<K>
extends java.lang.Object
implements java.util.Map<K,java.lang.Integer>, java.io.Serializable

Map implementation specialised for int values using open addressing and linear probing for cache efficient access. The implementation is mirror copy of Int2ObjectHashMap and it also relies on missing value concept from Int2IntHashMap

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	Object2IntHashMap.EntryIterator
class	Object2IntHashMap.EntrySet
class	Object2IntHashMap.KeyIterator
class	Object2IntHashMap.KeySet
class	Object2IntHashMap.ValueCollection
class	Object2IntHashMap.ValueIterator

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
Object2IntHashMap(int missingValue) Construct a map with default capacity and load factor.
Object2IntHashMap(int initialCapacity, float loadFactor, int missingValue) Construct a new map allowing a configuration for initial capacity and load factor.
Object2IntHashMap(int initialCapacity, float loadFactor, int missingValue, boolean shouldAvoidAllocation) Construct a new map allowing a configuration for initial capacity and load factor.
Object2IntHashMap(Object2IntHashMap<K> mapToCopy) Copy construct a new map from an existing one.

Method Summary

Modifier and Type	Method and Description
int	capacity() Get the total capacity for the map to which the load factor will be a fraction of.
void	clear()
void	compact() Compact the Map backing arrays by rehashing with a capacity just larger than current size and giving consideration to the load factor.
int	computeIfAbsent(K key, java.util.function.ToIntFunction<? super K> 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.
boolean	containsKey(java.lang.Object key) Overloaded version of Map.containsKey(Object) that takes a primitive int key.
boolean	containsValue(int value)
boolean	containsValue(java.lang.Object value)
Object2IntHashMap.EntrySet	entrySet()
boolean	equals(java.lang.Object o)
java.lang.Integer	get(java.lang.Object key)
int	getValue(K key) Overloaded version of Map.get(Object) that takes a primitive int key.
int	hashCode()
boolean	isEmpty()
Object2IntHashMap.KeySet	keySet()
float	loadFactor() Get the load factor beyond which the map will increase size.
int	missingValue() The value to be used as a null marker in the map.
int	put(K key, int value) Overloaded version of Map.put(Object, Object) that takes a primitive int key.
java.lang.Integer	put(K key, java.lang.Integer value)
void	putAll(java.util.Map<? extends K,? extends java.lang.Integer> map)
java.lang.Integer	remove(java.lang.Object key)
int	removeKey(K key) Overloaded version of Map.remove(Object) that takes a primitive int key.
int	replace(K key, int value) Primitive specialised version of Map.replace(Object, Object)
boolean	replace(K key, int oldValue, int newValue) Primitive specialised version of Map.replace(Object, Object, Object)
int	resizeThreshold() Get the actual threshold which when reached the map will resize.
int	size()
java.lang.String	toString()
Object2IntHashMap.ValueCollection	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

Object2IntHashMap

public Object2IntHashMap(int missingValue)

Construct a map with default capacity and load factor.

Parameters:

missingValue - value to be used as a null maker in the map

Object2IntHashMap

public Object2IntHashMap(int initialCapacity,
                         float loadFactor,
                         int missingValue)

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

missingValue - value to be used as a null marker in the map

Object2IntHashMap

public Object2IntHashMap(int initialCapacity,
                         float loadFactor,
                         int missingValue,
                         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

missingValue - value to be used as a null marker in the map

shouldAvoidAllocation - should allocation be avoided by caching iterators and map entries.

Object2IntHashMap

public Object2IntHashMap(Object2IntHashMap<K> mapToCopy)

Copy construct a new map from an existing one.

Parameters:

mapToCopy - for construction.

Method Detail

missingValue

public int missingValue()

The value to be used as a null marker in the map.

Returns:

value to be used as a null marker in the map.

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 java.util.Map<K,java.lang.Integer>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<K,java.lang.Integer>

containsKey

public boolean containsKey(java.lang.Object key)

Overloaded version of Map.containsKey(Object) that takes a primitive int key.

Specified by:

containsKey in interface java.util.Map<K,java.lang.Integer>

Parameters:

key - for indexing the Map

Returns:

true if the key is found otherwise false.

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<K,java.lang.Integer>

containsValue

public boolean containsValue(int value)

get

public java.lang.Integer get(java.lang.Object key)

Specified by:

get in interface java.util.Map<K,java.lang.Integer>

getValue

public int getValue(K key)

Overloaded version of Map.get(Object) that takes a primitive int key. Due to type erasure have to rename the method

Parameters:

key - for indexing the Map

Returns:

the value if found otherwise missingValue

computeIfAbsent

public int computeIfAbsent(K key,
                           java.util.function.ToIntFunction<? super K> 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(K, java.util.function.Function<? super K, ? extends V>).

Parameters:

key - to search on.

mappingFunction - to provide a value if the get returns missingValue.

Returns:

the value if found otherwise the default.

put

public java.lang.Integer put(K key,
                             java.lang.Integer value)

Specified by:

put in interface java.util.Map<K,java.lang.Integer>

put

public int put(K key,
               int 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 missingValue

remove

public java.lang.Integer remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<K,java.lang.Integer>

removeKey

public int removeKey(K key)

Overloaded version of Map.remove(Object) that takes a primitive int key. Due to type erasure have to rename the method

Parameters:

key - for indexing the Map

Returns:

the value if found otherwise missingValue

clear

public void clear()

Specified by:

clear in interface java.util.Map<K,java.lang.Integer>

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(java.util.Map<? extends K,? extends java.lang.Integer> map)

Specified by:

putAll in interface java.util.Map<K,java.lang.Integer>

keySet

public Object2IntHashMap.KeySet keySet()

Specified by:

keySet in interface java.util.Map<K,java.lang.Integer>

values

public Object2IntHashMap.ValueCollection values()

Specified by:

values in interface java.util.Map<K,java.lang.Integer>

entrySet

public Object2IntHashMap.EntrySet entrySet()

Specified by:

entrySet in interface java.util.Map<K,java.lang.Integer>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Specified by:

equals in interface java.util.Map<K,java.lang.Integer>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Map<K,java.lang.Integer>

Overrides:

hashCode in class java.lang.Object

replace

public int replace(K key,
                   int 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(K key,
                       int oldValue,
                       int 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