public class Reference2ObjectOpenHashMap<K,V> extends AbstractReference2ObjectMap<K,V> implements java.io.Serializable, java.lang.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, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create maps with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, 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.
Entries returned by the type-specific Reference2ObjectMap.entrySet()
method implement
the suitable type-specific Pair
interface;
only values are mutable.
Hash
,
HashCommon
,
Serialized FormAbstractReference2ObjectMap.BasicEntry<K,V>, AbstractReference2ObjectMap.BasicEntrySet<K,V>
Hash.Strategy<K>
Reference2ObjectMap.Entry<K,V>, Reference2ObjectMap.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 |
---|
Reference2ObjectOpenHashMap()
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ObjectOpenHashMap(int expected)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ObjectOpenHashMap(int expected,
float f)
Creates a new hash map.
|
Reference2ObjectOpenHashMap(K[] k,
V[] v)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
Reference2ObjectOpenHashMap(K[] k,
V[] v,
float f)
Creates a new hash map using the elements of two parallel arrays.
|
Reference2ObjectOpenHashMap(java.util.Map<? extends K,? extends V> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
Reference2ObjectOpenHashMap(java.util.Map<? extends K,? extends V> m,
float f)
Creates a new hash map copying a given one.
|
Reference2ObjectOpenHashMap(Reference2ObjectMap<K,V> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
Reference2ObjectOpenHashMap(Reference2ObjectMap<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 of the mappings from this map (optional operation).
|
Reference2ObjectOpenHashMap<K,V> |
clone()
Returns a deep copy of this map.
|
V |
compute(K k,
java.util.function.BiFunction<? super K,? 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). |
V |
computeIfAbsent(K key,
Reference2ObjectFunction<? super K,? extends V> mappingFunction)
If the specified key is not already associated with a value, attempts to compute its value
using the given mapping function and enters it into this map, unless the key is not present
in the given mapping function.
|
V |
computeIfPresent(K k,
java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
|
boolean |
containsKey(java.lang.Object k)
Returns true if this function contains a mapping for the specified key.
|
boolean |
containsValue(java.lang.Object v) |
V |
get(java.lang.Object k)
Returns the value to which the given key is mapped.
|
V |
getOrDefault(java.lang.Object k,
V defaultValue)
Returns the value to which the specified key is mapped, or the
defaultValue if this
map contains no mapping for the key. |
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 |
merge(K k,
V v,
java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
If the specified key is not already associated with a value, associates it with the given
value . |
V |
put(K k,
V v)
Adds a pair to the map (optional operation).
|
void |
putAll(java.util.Map<? extends K,? extends V> m) |
V |
putIfAbsent(K k,
V v)
If the specified key is not already associated with a value, associates it with the given
value and returns the default return value, else returns
the current value.
|
Reference2ObjectMap.FastEntrySet<K,V> |
reference2ObjectEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
V |
remove(java.lang.Object k)
Removes the mapping with the given key (optional operation).
|
boolean |
remove(java.lang.Object k,
java.lang.Object v)
Removes the entry for the specified key only if it is currently mapped to the specified value.
|
V |
replace(K k,
V v)
Replaces the entry for the specified key only if it is currently mapped to some value.
|
boolean |
replace(K k,
V oldValue,
V v)
Replaces the entry for the specified key only if currently mapped to the specified value.
|
int |
size()
Returns the number of key/value mappings in this map.
|
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.
|
equals, toString
defaultReturnValue, defaultReturnValue
computeObjectIfAbsentPartial, defaultReturnValue, defaultReturnValue, entrySet, forEach
andThenByte, andThenChar, andThenDouble, andThenFloat, andThenInt, andThenLong, andThenObject, andThenReference, andThenShort, composeByte, composeChar, composeDouble, composeFloat, composeInt, composeLong, composeObject, composeReference, composeShort
public Reference2ObjectOpenHashMap(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 map.f
- the load factor.public Reference2ObjectOpenHashMap(int expected)
Hash.DEFAULT_LOAD_FACTOR
as load factor.expected
- the expected number of elements in the hash map.public Reference2ObjectOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.public Reference2ObjectOpenHashMap(java.util.Map<? extends K,? extends V> m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Reference2ObjectOpenHashMap(java.util.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 Reference2ObjectOpenHashMap(Reference2ObjectMap<K,V> m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Reference2ObjectOpenHashMap(Reference2ObjectMap<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 Reference2ObjectOpenHashMap(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.java.lang.IllegalArgumentException
- if k
and v
have different lengths.public Reference2ObjectOpenHashMap(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.java.lang.IllegalArgumentException
- if k
and v
have different lengths.public void putAll(java.util.Map<? extends K,? extends V> m)
AbstractReference2ObjectMap
public V put(K k, V v)
Reference2ObjectMap
This default implementation just delegates to the corresponding function method.
put
in interface Reference2ObjectFunction<K,V>
put
in interface Reference2ObjectMap<K,V>
put
in interface java.util.Map<K,V>
k
- the key.v
- the value.Function.put(Object,Object)
public V remove(java.lang.Object k)
Reference2ObjectMap
This default implementation just delegates to the corresponding type-specific–function method.
remove
in interface Reference2ObjectFunction<K,V>
remove
in interface Reference2ObjectMap<K,V>
remove
in interface java.util.Map<K,V>
k
- the key.Function.remove(Object)
public V get(java.lang.Object k)
Reference2ObjectFunction
get
in interface Reference2ObjectFunction<K,V>
get
in interface java.util.Map<K,V>
k
- the key.Function.get(Object)
public boolean containsKey(java.lang.Object k)
AbstractReference2ObjectMap
containsKey
in interface Reference2ObjectMap<K,V>
containsKey
in interface java.util.Map<K,V>
containsKey
in class AbstractReference2ObjectMap<K,V>
k
- the key.key
.Map.containsKey(Object)
public boolean containsValue(java.lang.Object v)
AbstractReference2ObjectMap
containsValue
in interface java.util.Map<K,V>
containsValue
in class AbstractReference2ObjectMap<K,V>
public V getOrDefault(java.lang.Object k, V defaultValue)
defaultValue
if this
map contains no mapping for the key.getOrDefault
in interface Reference2ObjectFunction<K,V>
getOrDefault
in interface Reference2ObjectMap<K,V>
getOrDefault
in interface java.util.Map<K,V>
k
- the key.defaultValue
- the default mapping of the key.defaultValue
if this map contains no mapping for the key.Map.getOrDefault(Object, Object)
public V putIfAbsent(K k, V v)
putIfAbsent
in interface Reference2ObjectMap<K,V>
putIfAbsent
in interface java.util.Map<K,V>
k
- key with which the specified value is to be associated.v
- value to be associated with the specified key.Map.putIfAbsent(Object, Object)
public boolean remove(java.lang.Object k, java.lang.Object v)
remove
in interface Reference2ObjectMap<K,V>
remove
in interface java.util.Map<K,V>
k
- key with which the specified value is associated.v
- value expected to be associated with the specified key.true
if the value was removed.Map.remove(Object, Object)
public boolean replace(K k, V oldValue, V v)
replace
in interface Reference2ObjectMap<K,V>
replace
in interface java.util.Map<K,V>
k
- key with which the specified value is associated.oldValue
- value expected to be associated with the specified key.v
- value to be associated with the specified key.true
if the value was replaced.Map.replace(Object, Object, Object)
public V replace(K k, V v)
replace
in interface Reference2ObjectMap<K,V>
replace
in interface java.util.Map<K,V>
k
- key with which the specified value is associated.v
- value to be associated with the specified key.Map.replace(Object, Object)
public V computeIfAbsent(K key, Reference2ObjectFunction<? super K,? extends V> mappingFunction)
This version of computeIfAbsent()
uses a type-specific version of fastutil
's Function
.
Since Function
has a containsKey()
method, it is possible to avoid adding a key by having containsKey()
return false
for that key.
computeIfAbsent
in interface Reference2ObjectMap<K,V>
key
- key with which the specified value is to be associated.mappingFunction
- the function to compute a value.Map.computeIfAbsent(Object, java.util.function.Function)
public V computeIfPresent(K k, java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
computeIfPresent
in interface Reference2ObjectMap<K,V>
computeIfPresent
in interface java.util.Map<K,V>
k
- key with which the specified value is to be associated.remappingFunction
- the function to compute a value.Map.computeIfPresent(Object, java.util.function.BiFunction)
public V compute(K k, java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
null
if there is no current mapping).
If the function returns null
, the mapping is removed (or remains absent if initially absent).
If the function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.
compute
in interface Reference2ObjectMap<K,V>
compute
in interface java.util.Map<K,V>
k
- key with which the specified value is to be associated.remappingFunction
- the function to compute a value.Map.compute(Object, java.util.function.BiFunction)
public V merge(K k, V v, java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
value
.
Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null
.merge
in interface Reference2ObjectMap<K,V>
merge
in interface java.util.Map<K,V>
k
- key with which the resulting value is to be associated.v
- the value to be merged with the existing value associated with the key or, if no existing value is associated with the key, to be associated with the key.remappingFunction
- the function to recompute a value if present.Map.merge(Object, Object, java.util.function.BiFunction)
public void clear()
Reference2ObjectMap
public int size()
Reference2ObjectMap
Integer.MAX_VALUE
elements, returns Integer.MAX_VALUE
.public boolean isEmpty()
public Reference2ObjectMap.FastEntrySet<K,V> reference2ObjectEntrySet()
Reference2ObjectMap
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Map.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).
reference2ObjectEntrySet
in interface Reference2ObjectMap<K,V>
Map.entrySet()
public ReferenceSet<K> keySet()
AbstractReference2ObjectMap
The view is backed by the set returned by Map.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 Reference2ObjectMap<K,V>
keySet
in interface java.util.Map<K,V>
keySet
in class AbstractReference2ObjectMap<K,V>
Map.keySet()
public ObjectCollection<V> values()
AbstractReference2ObjectMap
The view is backed by the set returned by Map.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 Reference2ObjectMap<K,V>
values
in interface java.util.Map<K,V>
values
in class AbstractReference2ObjectMap<K,V>
Map.values()
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 Reference2ObjectOpenHashMap<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.
clone
in class java.lang.Object
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.