public class Reference2ReferenceOpenHashMap<K,V> extends AbstractReference2ReferenceMap<K,V> implements Serializable, Cloneable, Hash
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.
Hash
,
HashCommon
,
Serialized FormAbstractReference2ReferenceMap.BasicEntry<K,V>
Hash.Strategy<K>
Reference2ReferenceMap.Entry<K,V>, Reference2ReferenceMap.FastEntrySet<K,V>
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
Constructor and Description |
---|
Reference2ReferenceOpenHashMap()
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ReferenceOpenHashMap(int expected)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ReferenceOpenHashMap(int expected,
float f)
Creates a new hash map.
|
Reference2ReferenceOpenHashMap(K[] k,
V[] v)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
Reference2ReferenceOpenHashMap(K[] k,
V[] v,
float f)
Creates a new hash map using the elements of two parallel arrays.
|
Reference2ReferenceOpenHashMap(Map<? extends K,? extends V> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
Reference2ReferenceOpenHashMap(Map<? extends K,? extends V> m,
float f)
Creates a new hash map copying a given one.
|
Reference2ReferenceOpenHashMap(Reference2ReferenceMap<K,V> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
Reference2ReferenceOpenHashMap(Reference2ReferenceMap<K,V> m,
float f)
Creates a new hash map copying a given type-specific one.
|
Modifier and Type | Method and Description |
---|---|
void |
clear()
Removes all associations from this function (optional operation).
|
Reference2ReferenceOpenHashMap<K,V> |
clone()
Returns a deep copy of this map.
|
boolean |
containsKey(Object k)
Checks whether the given value is contained in
AbstractReference2ReferenceMap.keySet() . |
boolean |
containsValue(Object v)
Checks whether the given value is contained in
AbstractReference2ReferenceMap.values() . |
V |
get(Object k)
Returns the value associated by this function to the specified key.
|
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.
|
boolean |
isEmpty() |
ReferenceSet<K> |
keySet()
Returns a type-specific-set view of the keys of this map.
|
V |
put(K k,
V v)
Associates the specified value with the specified key in this function (optional operation).
|
void |
putAll(Map<? extends K,? extends V> m)
Puts all pairs in the given map.
|
Reference2ReferenceMap.FastEntrySet<K,V> |
reference2ReferenceEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
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).
|
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.
|
ReferenceCollection<V> |
values()
Returns a type-specific-set view of the values of this map.
|
entrySet, equals, toString
defaultReturnValue, defaultReturnValue
defaultReturnValue, defaultReturnValue
public Reference2ReferenceOpenHashMap(int expected, float f)
The actual table size will be the least power of two greater than expected
/f
.
expected
- the expected number of elements in the hash set.f
- the load factor.public Reference2ReferenceOpenHashMap(int expected)
Hash.DEFAULT_LOAD_FACTOR
as load factor.expected
- the expected number of elements in the hash map.public Reference2ReferenceOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.public Reference2ReferenceOpenHashMap(Map<? extends K,? extends V> m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Reference2ReferenceOpenHashMap(Map<? extends K,? extends V> m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.m
- a Map
to be copied into the new hash map.public Reference2ReferenceOpenHashMap(Reference2ReferenceMap<K,V> m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Reference2ReferenceOpenHashMap(Reference2ReferenceMap<K,V> m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific one.m
- a type-specific map to be copied into the new hash map.public Reference2ReferenceOpenHashMap(K[] k, V[] v, float f)
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.IllegalArgumentException
- if k
and v
have different lengths.public Reference2ReferenceOpenHashMap(K[] k, V[] v)
Hash.DEFAULT_LOAD_FACTOR
as load factor using the elements of two parallel arrays.k
- the array of keys of the new hash map.v
- the array of corresponding values in the new hash map.IllegalArgumentException
- if k
and v
have different lengths.public void putAll(Map<? extends K,? extends V> m)
public V put(K k, V v)
Function
public V remove(Object k)
Function
public V get(Object k)
Function
public boolean containsKey(Object k)
AbstractReference2ReferenceMap
AbstractReference2ReferenceMap.keySet()
.containsKey
in interface Function<K,V>
containsKey
in interface Map<K,V>
containsKey
in class AbstractReference2ReferenceMap<K,V>
k
- the key.key
.Map.containsKey(Object)
public boolean containsValue(Object v)
AbstractReference2ReferenceMap
AbstractReference2ReferenceMap.values()
.containsValue
in interface Map<K,V>
containsValue
in class AbstractReference2ReferenceMap<K,V>
public void clear()
Function
public int size()
Function
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.
public boolean isEmpty()
@Deprecated public void growthFactor(int growthFactor)
fastutil
6.1.0, hash tables are doubled when they are too full.growthFactor
- unused.@Deprecated public int growthFactor()
fastutil
6.1.0, hash tables are doubled when they are too full.growthFactor(int)
public Reference2ReferenceMap.FastEntrySet<K,V> reference2ReferenceEntrySet()
Reference2ReferenceMap
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Reference2ReferenceMap.entrySet()
so that it returns an ObjectSet
of objects of type Map.Entry
(the latter makes it possible to
access keys and values with type-specific methods).
reference2ReferenceEntrySet
in interface Reference2ReferenceMap<K,V>
Reference2ReferenceMap.entrySet()
public ReferenceSet<K> keySet()
AbstractReference2ReferenceMap
The view is backed by the set returned by AbstractReference2ReferenceMap.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.
keySet
in interface Reference2ReferenceMap<K,V>
keySet
in interface Map<K,V>
keySet
in class AbstractReference2ReferenceMap<K,V>
Map.keySet()
public ReferenceCollection<V> values()
AbstractReference2ReferenceMap
The view is backed by the set returned by AbstractReference2ReferenceMap.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.
values
in interface Reference2ReferenceMap<K,V>
values
in interface Map<K,V>
values
in class AbstractReference2ReferenceMap<K,V>
Map.values()
@Deprecated public boolean rehash()
If you need to reduce the table size to fit exactly
this set, use trim()
.
trim()
public boolean trim()
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.
trim(int)
public boolean trim(int n)
Let N be the smallest table size that can hold
max(n,
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.
size()
)
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.
n
- the threshold for the trimming.trim()
public Reference2ReferenceOpenHashMap<K,V> clone()
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.
public int hashCode()
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.