it.unimi.dsi.fastutil.ints

Class Int2ObjectOpenHashMap<V>

java.lang.Object

it.unimi.dsi.fastutil.ints.AbstractInt2ObjectFunction<V>

it.unimi.dsi.fastutil.ints.AbstractInt2ObjectMap<V>

it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap<V>

All Implemented Interfaces:

Function<java.lang.Integer,V>, Hash, Int2ObjectFunction<V>, Int2ObjectMap<V>, java.io.Serializable, java.lang.Cloneable, java.util.Map<java.lang.Integer,V>

public class Int2ObjectOpenHashMap<V>
extends AbstractInt2ObjectMap<V>
implements java.io.Serializable, java.lang.Cloneable, Hash

A type-specific hash map with a fast, small-footprint implementation.

Instances of this class use a hash table to represent a map. The table is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size. However, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.

Note that clear() does not modify the hash table size. Rather, a family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class.

See Also:

Hash, HashCommon, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.ints.AbstractInt2ObjectMap

AbstractInt2ObjectMap.BasicEntry<V>

Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash

Hash.Strategy<K>

Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.ints.Int2ObjectMap

Int2ObjectMap.Entry<V>, Int2ObjectMap.FastEntrySet<V>

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	containsNullKey Whether this set contains the key zero.
protected Int2ObjectMap.FastEntrySet<V>	entries Cached set of entries.
protected float	f The acceptable load factor.
protected int[]	key The array of keys.
protected IntSet	keys Cached set of keys.
protected int	mask The mask for wrapping a position counter.
protected int	maxFill Threshold after which we rehash.
protected int	n The current table size.
protected int	size Number of entries in the set (including the key zero, if present).
protected V[]	value The array of values.
protected ObjectCollection<V>	values Cached collection of values.

Fields inherited from class it.unimi.dsi.fastutil.ints.AbstractInt2ObjectFunction

defRetValue

Fields inherited from interface it.unimi.dsi.fastutil.Hash

DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR

Constructor Summary

Constructors

Constructor and Description
Int2ObjectOpenHashMap() Creates a new hash map with initial expected Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor.
Int2ObjectOpenHashMap(int expected) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor.
Int2ObjectOpenHashMap(int[] k, V[] v) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays.
Int2ObjectOpenHashMap(int[] k, V[] v, float f) Creates a new hash map using the elements of two parallel arrays.
Int2ObjectOpenHashMap(Int2ObjectMap<V> m) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one.
Int2ObjectOpenHashMap(Int2ObjectMap<V> m, float f) Creates a new hash map copying a given type-specific one.
Int2ObjectOpenHashMap(int expected, float f) Creates a new hash map.
Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one.
Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m, float f) Creates a new hash map copying a given one.

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all associations from this function (optional operation).
Int2ObjectOpenHashMap<V>	clone() Returns a deep copy of this map.
boolean	containsKey(int k) Checks whether the given value is contained in AbstractInt2ObjectMap.keySet().
boolean	containsValue(java.lang.Object v) Checks whether the given value is contained in AbstractInt2ObjectMap.values().
V	get(int k) Returns the value to which the given key is mapped.
V	get(java.lang.Integer ok) Deprecated. Please use the corresponding type-specific method instead.
int	growthFactor() Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.
void	growthFactor(int growthFactor) Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.
int	hashCode() Returns a hash code for this map.
Int2ObjectMap.FastEntrySet<V>	int2ObjectEntrySet() Returns a type-specific set view of the mappings contained in this map.
boolean	isEmpty()
IntSet	keySet() Returns a type-specific-set view of the keys of this map.
V	put(java.lang.Integer ok, V ov) Deprecated. Please use the corresponding type-specific method instead.
V	put(int k, V v) Adds a pair to the map.
void	putAll(java.util.Map<? extends java.lang.Integer,? extends V> m) Puts all pairs in the given map.
boolean	rehash() Deprecated. A no-op.
protected void	rehash(int newN) Rehashes the map.
V	remove(int k) Removes the mapping with the given key.
V	remove(java.lang.Object ok) Deprecated. Please use the corresponding type-specific method instead.
protected void	shiftKeys(int pos) Shifts left entries with the specified hash code, starting at the specified position, and empties the resulting free entry.
int	size() Returns the intended number of keys in this function, or -1 if no such number exists.
boolean	trim() Rehashes the map, making the table as small as possible.
boolean	trim(int n) Rehashes this map if the table is too large.
ObjectCollection<V>	values() Returns a type-specific-set view of the values of this map.

Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractInt2ObjectMap

entrySet, equals, toString

Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractInt2ObjectFunction

containsKey, defaultReturnValue, defaultReturnValue, get

Methods inherited from class java.lang.Object

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

Methods inherited from interface it.unimi.dsi.fastutil.ints.Int2ObjectFunction

defaultReturnValue, defaultReturnValue

Methods inherited from interface it.unimi.dsi.fastutil.Function

containsKey, get

Methods inherited from interface java.util.Map

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

Field Detail

key

protected transient int[] key

The array of keys.

value

protected transient V[] value

The array of values.

mask

protected transient int mask

The mask for wrapping a position counter.

containsNullKey

protected transient boolean containsNullKey

Whether this set contains the key zero.

n

protected transient int n

The current table size.

maxFill

protected transient int maxFill

Threshold after which we rehash. It must be the table size times f.

size

protected int size

Number of entries in the set (including the key zero, if present).

f

protected final float f

The acceptable load factor.

entries

protected transient Int2ObjectMap.FastEntrySet<V> entries

Cached set of entries.

keys

protected transient IntSet keys

Cached set of keys.

values

protected transient ObjectCollection<V> values

Cached collection of values.

Constructor Detail

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int expected,
                             float f)

Creates a new hash map.

The actual table size will be the least power of two greater than expected/f.

Parameters:

expected - the expected number of elements in the hash set.

f - the load factor.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int expected)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor.

Parameters:

expected - the expected number of elements in the hash map.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap()

Creates a new hash map with initial expected Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m,
                             float f)

Creates a new hash map copying a given one.

Parameters:

m - a Map to be copied into the new hash map.

f - the load factor.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one.

Parameters:

m - a Map to be copied into the new hash map.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(Int2ObjectMap<V> m,
                             float f)

Creates a new hash map copying a given type-specific one.

Parameters:

m - a type-specific map to be copied into the new hash map.

f - the load factor.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(Int2ObjectMap<V> m)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one.

Parameters:

m - a type-specific map to be copied into the new hash map.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int[] k,
                             V[] v,
                             float f)

Creates a new hash map using the elements of two parallel arrays.

Parameters:

k - the array of keys of the new hash map.

v - the array of corresponding values in the new hash map.

f - the load factor.

Throws:

java.lang.IllegalArgumentException - if k and v have different lengths.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int[] k,
                             V[] v)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays.

Parameters:

k - the array of keys of the new hash map.

v - the array of corresponding values in the new hash map.

Throws:

java.lang.IllegalArgumentException - if k and v have different lengths.

Method Detail

putAll

public void putAll(java.util.Map<? extends java.lang.Integer,? extends V> m)

Puts all pairs in the given map. If the map implements the interface of this map, it uses the faster iterators.

Specified by:

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

Overrides:

putAll in class AbstractInt2ObjectMap<V>

Parameters:

m - a map.

put

public V put(int k,
             V v)

Description copied from interface: Int2ObjectFunction

Adds a pair to the map.

Specified by:

put in interface Int2ObjectFunction<V>

Overrides:

put in class AbstractInt2ObjectFunction<V>

Parameters:

k - the key.

v - the value.

Returns:

the old value, or the default return value if no value was present for the given key.

See Also:

Function.put(Object,Object)

put

@Deprecated
public V put(java.lang.Integer ok,
                         V ov)

Deprecated. Please use the corresponding type-specific method instead.

Delegates to the corresponding type-specific method, taking care of returning null on a missing key.

This method must check whether the provided key is in the map using containsKey(). Thus, it probes the map twice. Implementors of subclasses should override it with a more efficient method.

Specified by:

put in interface Function<java.lang.Integer,V>

Specified by:

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

Overrides:

put in class AbstractInt2ObjectFunction<V>

Parameters:

ok - the key.

ov - the value.

Returns:

the old value, or null if no value was present for the given key.

See Also:

Map.put(Object,Object)

shiftKeys

protected final void shiftKeys(int pos)

Shifts left entries with the specified hash code, starting at the specified position, and empties the resulting free entry.

Parameters:

pos - a starting position.

remove

public V remove(int k)

Description copied from interface: Int2ObjectFunction

Removes the mapping with the given key.

Specified by:

remove in interface Int2ObjectFunction<V>

Overrides:

remove in class AbstractInt2ObjectFunction<V>

Parameters:

k - the key.

Returns:

the old value, or the default return value if no value was present for the given key.

See Also:

Function.remove(Object)

remove

@Deprecated
public V remove(java.lang.Object ok)

Deprecated. Please use the corresponding type-specific method instead.

Delegates to the corresponding type-specific method, taking care of returning null on a missing key.

This method must check whether the provided key is in the map using containsKey(). Thus, it probes the map twice. Implementors of subclasses should override it with a more efficient method.

Specified by:

remove in interface Function<java.lang.Integer,V>

Specified by:

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

Overrides:

remove in class AbstractInt2ObjectFunction<V>

Parameters:

ok - the key.

Returns:

the old value, or null if no value was present for the given key.

See Also:

Map.remove(Object)

get

@Deprecated
public V get(java.lang.Integer ok)

Deprecated. Please use the corresponding type-specific method instead.

get

public V get(int k)

Description copied from interface: Int2ObjectFunction

Returns the value to which the given key is mapped.

Specified by:

get in interface Int2ObjectFunction<V>

Parameters:

k - the key.

Returns:

the corresponding value, or the default return value if no value was present for the given key.

See Also:

Function.get(Object)

containsKey

public boolean containsKey(int k)

Description copied from class: AbstractInt2ObjectMap

Checks whether the given value is contained in AbstractInt2ObjectMap.keySet().

Specified by:

containsKey in interface Int2ObjectFunction<V>

Overrides:

containsKey in class AbstractInt2ObjectMap<V>

See Also:

Function.containsKey(Object)

containsValue

public boolean containsValue(java.lang.Object v)

Description copied from class: AbstractInt2ObjectMap

Checks whether the given value is contained in AbstractInt2ObjectMap.values().

Specified by:

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

Overrides:

containsValue in class AbstractInt2ObjectMap<V>

clear

public void clear()

Description copied from interface: Function

Removes all associations from this function (optional operation).

Specified by:

clear in interface Function<java.lang.Integer,V>

Specified by:

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

Overrides:

clear in class AbstractInt2ObjectFunction<V>

See Also:

Map.clear()

size

public int size()

Description copied from interface: Function

Returns the intended number of keys in this function, or -1 if no such number exists.

Most function implementations will have some knowledge of the intended number of keys in their domain. In some cases, however, this might not be possible.

Specified by:

size in interface Function<java.lang.Integer,V>

Specified by:

size in interface java.util.Map<java.lang.Integer,V>

Returns:

the intended number of keys in this function, or -1 if that number is not available.

isEmpty

public boolean isEmpty()

Specified by:

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

Overrides:

isEmpty in class AbstractInt2ObjectMap<V>

growthFactor

@Deprecated
public void growthFactor(int growthFactor)

Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.

A no-op for backward compatibility.

Parameters:

growthFactor - unused.

growthFactor

@Deprecated
public int growthFactor()

Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.

Gets the growth factor (2).

Returns:

the growth factor of this set, which is fixed (2).

See Also:

growthFactor(int)

int2ObjectEntrySet

public Int2ObjectMap.FastEntrySet<V> int2ObjectEntrySet()

Description copied from interface: Int2ObjectMap

Returns a type-specific set view of the mappings contained in this map.

This method is necessary because there is no inheritance along type parameters: it is thus impossible to strengthen Int2ObjectMap.entrySet() so that it returns an ObjectSet of type-specific entries (the latter makes it possible to access keys and values with type-specific methods).

Specified by:

int2ObjectEntrySet in interface Int2ObjectMap<V>

Returns:

a type-specific set view of the mappings contained in this map.

See Also:

Int2ObjectMap.entrySet()

keySet

public IntSet keySet()

Description copied from class: AbstractInt2ObjectMap

Returns a type-specific-set view of the keys of this map.

The view is backed by the set returned by AbstractInt2ObjectMap.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:

keySet in interface Int2ObjectMap<V>

Specified by:

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

Overrides:

keySet in class AbstractInt2ObjectMap<V>

Returns:

a set view of the keys of this map; it may be safely cast to a type-specific interface.

See Also:

Map.keySet()

values

public ObjectCollection<V> values()

Description copied from class: AbstractInt2ObjectMap

Returns a type-specific-set view of the values of this map.

The view is backed by the set returned by AbstractInt2ObjectMap.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:

values in interface Int2ObjectMap<V>

Specified by:

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

Overrides:

values in class AbstractInt2ObjectMap<V>

Returns:

a set view of the values of this map; it may be safely cast to a type-specific interface.

See Also:

Map.values()

rehash

@Deprecated
public boolean rehash()

Deprecated. A no-op.

A no-op for backward compatibility. The kind of tables implemented by this class never need rehashing.

If you need to reduce the table size to fit exactly this set, use trim().

Returns:

true.

See Also:

trim()

trim

public boolean trim()

Rehashes the map, making the table as small as possible.

This method rehashes the table to the smallest size satisfying the load factor. It can be used when the set will not be changed anymore, so to optimize access speed and size.

If the table size is already the minimum possible, this method does nothing.

Returns:

true if there was enough memory to trim the map.

See Also:

trim(int)

trim

public boolean trim(int n)

Rehashes this map if the table is too large.

Let N be the smallest table size that can hold max(n,size()) entries, still satisfying the load factor. If the current table size is smaller than or equal to N, this method does nothing. Otherwise, it rehashes this map in a table of size N.

This method is useful when reusing maps. Clearing a map leaves the table size untouched. If you are reusing a map many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient maps.

Parameters:

n - the threshold for the trimming.

Returns:

true if there was enough memory to trim the map.

See Also:

trim()

rehash

protected void rehash(int newN)

Rehashes the map.

This method implements the basic rehashing strategy, and may be overriden by subclasses implementing different rehashing strategies (e.g., disk-based rehashing). However, you should not override this method unless you understand the internal workings of this class.

Parameters:

newN - the new size

clone

public Int2ObjectOpenHashMap<V> clone()

Returns a deep copy of this map.

This method performs a deep copy of this hash map; the data stored in the map, however, is not cloned. Note that this makes a difference only for object keys.

Overrides:

clone in class java.lang.Object

Returns:

a deep copy of this map.

hashCode

public int hashCode()

Returns a hash code for this map. This method overrides the generic method provided by the superclass. Since equals() is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method.

Specified by:

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

Overrides:

hashCode in class AbstractInt2ObjectMap<V>

Returns:

a hash code for this map.