it.unimi.dsi.fastutil.objects
Class Object2ObjectLinkedOpenHashMap<K,V>

java.lang.Object
  it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction<K,V>
      it.unimi.dsi.fastutil.objects.AbstractObject2ObjectMap<K,V>
          it.unimi.dsi.fastutil.objects.AbstractObject2ObjectSortedMap<K,V>
              it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenHashMap<K,V>

All Implemented Interfaces:

Function<K,V>, Hash, Object2ObjectFunction<K,V>, Object2ObjectMap<K,V>, Object2ObjectSortedMap<K,V>, Serializable, Cloneable, Map<K,V>, SortedMap<K,V>

public class Object2ObjectLinkedOpenHashMap<K,V>
extends AbstractObject2ObjectSortedMap<K,V>
implements Serializable, Cloneable, Hash

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

Instances of this class use a hash table to represent a map. The table is enlarged as needed by doubling its size when new entries are created, but it is never made smaller (even on a clear()). A family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class.

Iterators generated by this map will enumerate pairs in the same order in which they have been added to the map (addition of pairs whose key is already present in the set does not change the iteration order). Note that this order has nothing in common with the natural order of the keys. The order is kept by means of a doubly linked list, represented via an array of longs parallel to the table.

This class implements the interface of a sorted map, so to allow easy access of the iteration order: for instance, you can get the first key in iteration order with firstKey() without having to create an iterator; however, this class partially violates the SortedMap contract because all submap methods throw an exception and comparator() returns always null.

Additional methods, such as getAndMoveToFirst(), make it easy to use instances of this class as a cache (e.g., with LRU policy).

The iterators provided by the views of this class using are type-specific list iterators, and can be started at any element which is a key of the map, or a NoSuchElementException exception will be thrown. If, however, the provided element is not the first or last key in the set, the first access to the list index will require linear time, as in the worst case the entire key set must be scanned in iteration order to retrieve the positional index of the starting key. If you use just the methods of a type-specific BidirectionalIterator, however, all operations will be performed in constant time.

See Also:

Hash, HashCommon, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectMap

AbstractObject2ObjectMap.BasicEntry<K,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.objects.Object2ObjectSortedMap

Object2ObjectSortedMap.FastSortedEntrySet<K,V>

Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.objects.Object2ObjectMap

Object2ObjectMap.Entry<K,V>, Object2ObjectMap.FastEntrySet<K,V>

Field Summary

static long

serialVersionUID

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

Object2ObjectLinkedOpenHashMap()
Creates a new hash map with initial expected Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor.

Object2ObjectLinkedOpenHashMap(int expected)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor.

Object2ObjectLinkedOpenHashMap(int expected, float f)
Creates a new hash map.

Object2ObjectLinkedOpenHashMap(K[] k, V[] v)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays.

Object2ObjectLinkedOpenHashMap(K[] k, V[] v, float f)
Creates a new hash map using the elements of two parallel arrays.

Object2ObjectLinkedOpenHashMap(Map<? extends K,? extends V> m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one.

Object2ObjectLinkedOpenHashMap(Map<? extends K,? extends V> m, float f)
Creates a new hash map copying a given one.

Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,V> m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one.

Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,V> m, float f)
Creates a new hash map copying a given type-specific one.

Method Summary

void	clear() Removes all associations from this function (optional operation).
Object2ObjectLinkedOpenHashMap<K,V>	clone() Returns a deep copy of this map.
Comparator<? super K>	comparator() Returns the comparator associated with this sorted set, or null if it uses its keys' natural ordering.
boolean	containsKey(Object k) Checks whether the given value is contained in AbstractObject2ObjectMap.keySet().
boolean	containsValue(Object v) Checks whether the given value is contained in AbstractObject2ObjectMap.values().
K	firstKey() Returns the first key of this map in iteration order.
V	get(Object k) Returns the value associated by this function to the specified key.
V	getAndMoveToFirst(K k) Returns the value to which the given key is mapped; if the key is present, it is moved to the first position of the iteration order.
V	getAndMoveToLast(K k) Returns the value to which the given key is mapped; if the key is present, it is moved to the last position of the iteration order.
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.
Object2ObjectSortedMap<K,V>	headMap(K to) Returns a view of the portion of this sorted map whose keys are strictly less than toKey.
boolean	isEmpty()
ObjectSortedSet<K>	keySet() Returns a type-specific-sorted-set view of the keys of this map.
K	lastKey() Returns the last key of this map in iteration order.
Object2ObjectSortedMap.FastSortedEntrySet<K,V>	object2ObjectEntrySet() Returns a type-specific sorted-set view of the mappings contained in this map.
V	put(K k, V v) Associates the specified value with the specified key in this function (optional operation).
V	putAndMoveToFirst(K k, V v) Adds a pair to the map; if the key is already present, it is moved to the first position of the iteration order.
V	putAndMoveToLast(K k, V v) Adds a pair to the map; if the key is already present, it is moved to the last position of the iteration order.
boolean	rehash() Deprecated. A no-op.
V	remove(Object k) Removes this key and the associated value from this function if it is present (optional operation).
V	removeFirst() Removes the mapping associated with the first key in iteration order.
V	removeLast() Removes the mapping associated with the last key in iteration order.
int	size() Returns the intended number of keys in this function, or -1 if no such number exists.
Object2ObjectSortedMap<K,V>	subMap(K from, K to) Returns a view of the portion of this sorted map whose keys range from fromKey, inclusive, to toKey, exclusive.
Object2ObjectSortedMap<K,V>	tailMap(K from) Returns a view of the portion of this sorted map whose keys are greater than or equal to fromKey.
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 collection view of the values contained in this map.

Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectSortedMap

entrySet

Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectMap

equals, putAll, toString

Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction

defaultReturnValue, defaultReturnValue

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2ObjectFunction

defaultReturnValue, defaultReturnValue

Methods inherited from interface java.util.Map

equals, putAll

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(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.

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(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.

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap()

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

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(Map<? extends K,? 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.

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(Map<? extends K,? 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.

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,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.

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,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.

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(K[] 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:

IllegalArgumentException - if k and v have different lengths.

Object2ObjectLinkedOpenHashMap

public Object2ObjectLinkedOpenHashMap(K[] 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:

IllegalArgumentException - if k and v have different lengths.

Method Detail

put

public V put(K k,
             V v)

Description copied from interface: Function

Associates the specified value with the specified key in this function (optional operation).

Specified by:

put in interface Function<K,V>

Specified by:

put in interface Map<K,V>

Overrides:

put in class AbstractObject2ObjectFunction<K,V>

Parameters:

k - the key.

v - the value.

Returns:

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

See Also:

Map.put(Object,Object)

remove

public V remove(Object k)

Description copied from interface: Function

Removes this key and the associated value from this function if it is present (optional operation).

Specified by:

remove in interface Function<K,V>

Specified by:

remove in interface Map<K,V>

Overrides:

remove in class AbstractObject2ObjectFunction<K,V>

Returns:

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

See Also:

Map.remove(Object)

removeFirst

public V removeFirst()

Removes the mapping associated with the first key in iteration order.

Returns:

the value previously associated with the first key in iteration order.

Throws:

NoSuchElementException - is this map is empty.

removeLast

public V removeLast()

Removes the mapping associated with the last key in iteration order.

Returns:

the value previously associated with the last key in iteration order.

Throws:

NoSuchElementException - is this map is empty.

getAndMoveToFirst

public V getAndMoveToFirst(K k)

Returns the value to which the given key is mapped; if the key is present, it is moved to the first position of the iteration order.

Parameters:

k - the key.

Returns:

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

getAndMoveToLast

public V getAndMoveToLast(K k)

Returns the value to which the given key is mapped; if the key is present, it is moved to the last position of the iteration order.

Parameters:

k - the key.

Returns:

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

putAndMoveToFirst

public V putAndMoveToFirst(K k,
                           V v)

Adds a pair to the map; if the key is already present, it is moved to the first position of the iteration order.

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.

putAndMoveToLast

public V putAndMoveToLast(K k,
                          V v)

Adds a pair to the map; if the key is already present, it is moved to the last position of the iteration order.

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.

get

public V get(Object k)

Description copied from interface: Function

Returns the value associated by this function to the specified key.

Specified by:

get in interface Function<K,V>

Specified by:

get in interface Map<K,V>

Parameters:

k - the key.

Returns:

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

See Also:

Map.get(Object)

containsKey

public boolean containsKey(Object k)

Description copied from class: AbstractObject2ObjectMap

Checks whether the given value is contained in AbstractObject2ObjectMap.keySet().

Specified by:

containsKey in interface Function<K,V>

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class AbstractObject2ObjectMap<K,V>

Parameters:

k - the key.

Returns:

true if this function associates a value to key.

See Also:

Map.containsKey(Object)

containsValue

public boolean containsValue(Object v)

Description copied from class: AbstractObject2ObjectMap

Checks whether the given value is contained in AbstractObject2ObjectMap.values().

Specified by:

containsValue in interface Map<K,V>

Overrides:

containsValue in class AbstractObject2ObjectMap<K,V>

clear

public void clear()

Description copied from interface: Function

Removes all associations from this function (optional operation).

Specified by:

clear in interface Function<K,V>

Specified by:

clear in interface Map<K,V>

Overrides:

clear in class AbstractObject2ObjectFunction<K,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<K,V>

Specified by:

size in interface Map<K,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 Map<K,V>

Overrides:

isEmpty in class AbstractObject2ObjectMap<K,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)

firstKey

public K firstKey()

Returns the first key of this map in iteration order.

Specified by:

firstKey in interface SortedMap<K,V>

Returns:

the first key in iteration order.

lastKey

public K lastKey()

Returns the last key of this map in iteration order.

Specified by:

lastKey in interface SortedMap<K,V>

Returns:

the last key in iteration order.

comparator

public Comparator<? super K> comparator()

Description copied from interface: Object2ObjectSortedMap

Returns the comparator associated with this sorted set, or null if it uses its keys' natural ordering.

Note that this specification strengthens the one given in SortedMap.comparator().

Specified by:

comparator in interface Object2ObjectSortedMap<K,V>

Specified by:

comparator in interface SortedMap<K,V>

See Also:

SortedMap.comparator()

tailMap

public Object2ObjectSortedMap<K,V> tailMap(K from)

Description copied from interface: Object2ObjectSortedMap

Returns a view of the portion of this sorted map whose keys are greater than or equal to fromKey.

Note that this specification strengthens the one given in SortedMap.tailMap(Object).

Specified by:

tailMap in interface Object2ObjectSortedMap<K,V>

Specified by:

tailMap in interface SortedMap<K,V>

See Also:

SortedMap.tailMap(Object)

headMap

public Object2ObjectSortedMap<K,V> headMap(K to)

Description copied from interface: Object2ObjectSortedMap

Returns a view of the portion of this sorted map whose keys are strictly less than toKey.

Note that this specification strengthens the one given in SortedMap.headMap(Object).

Specified by:

headMap in interface Object2ObjectSortedMap<K,V>

Specified by:

headMap in interface SortedMap<K,V>

See Also:

SortedMap.headMap(Object)

subMap

public Object2ObjectSortedMap<K,V> subMap(K from,
                                          K to)

Description copied from interface: Object2ObjectSortedMap

Returns a view of the portion of this sorted map whose keys range from fromKey, inclusive, to toKey, exclusive.

Note that this specification strengthens the one given in SortedMap.subMap(Object,Object).

Specified by:

subMap in interface Object2ObjectSortedMap<K,V>

Specified by:

subMap in interface SortedMap<K,V>

See Also:

SortedMap.subMap(Object,Object)

object2ObjectEntrySet

public Object2ObjectSortedMap.FastSortedEntrySet<K,V> object2ObjectEntrySet()

Description copied from interface: Object2ObjectSortedMap

Returns a type-specific sorted-set view of the mappings contained in this map. Note that this specification strengthens the one given in the corresponding type-specific unsorted map.

Specified by:

object2ObjectEntrySet in interface Object2ObjectMap<K,V>

Specified by:

object2ObjectEntrySet in interface Object2ObjectSortedMap<K,V>

Returns:

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

See Also:

Object2ObjectSortedMap.entrySet()

keySet

public ObjectSortedSet<K> keySet()

Description copied from class: AbstractObject2ObjectSortedMap

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

The view is backed by the sorted set returned by AbstractObject2ObjectSortedMap.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 Object2ObjectMap<K,V>

Specified by:

keySet in interface Object2ObjectSortedMap<K,V>

Specified by:

keySet in interface Map<K,V>

Specified by:

keySet in interface SortedMap<K,V>

Overrides:

keySet in class AbstractObject2ObjectSortedMap<K,V>

Returns:

a sorted 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: AbstractObject2ObjectSortedMap

Returns a type-specific collection view of the values contained in this map.

The view is backed by the sorted set returned by AbstractObject2ObjectSortedMap.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 Object2ObjectMap<K,V>

Specified by:

values in interface Object2ObjectSortedMap<K,V>

Specified by:

values in interface Map<K,V>

Specified by:

values in interface SortedMap<K,V>

Overrides:

values in class AbstractObject2ObjectSortedMap<K,V>

Returns:

a type-specific collection view of the values contained in this map.

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()

clone

public Object2ObjectLinkedOpenHashMap<K,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 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 Map<K,V>

Overrides:

hashCode in class AbstractObject2ObjectMap<K,V>

Returns:

a hash code for this map.