public class Char2CharOpenHashMap extends AbstractChar2CharMap implements Serializable, Cloneable, Hash
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.
Warning: The implementation of this class has significantly
changed in fastutil
6.1.0. Please read the
comments about this issue in the section “Faster Hash Tables” of the overview.
Hash
,
HashCommon
,
Serialized FormAbstractChar2CharMap.BasicEntry
Hash.Strategy<K>
Char2CharMap.Entry, Char2CharMap.FastEntrySet
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
Constructor and Description |
---|
Char2CharOpenHashMap()
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
Char2CharOpenHashMap(char[] k,
char[] v)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
Char2CharOpenHashMap(char[] k,
char[] v,
float f)
Creates a new hash map using the elements of two parallel arrays.
|
Char2CharOpenHashMap(Char2CharMap m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
Char2CharOpenHashMap(Char2CharMap m,
float f)
Creates a new hash map copying a given type-specific one.
|
Char2CharOpenHashMap(int expected)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Char2CharOpenHashMap(int expected,
float f)
Creates a new hash map.
|
Char2CharOpenHashMap(Map<? extends Character,? extends Character> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
Char2CharOpenHashMap(Map<? extends Character,? extends Character> m,
float f)
Creates a new hash map copying a given one.
|
Modifier and Type | Method and Description |
---|---|
Char2CharMap.FastEntrySet |
char2CharEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
void |
clear()
Removes all associations from this function (optional operation).
|
Char2CharOpenHashMap |
clone()
Returns a deep copy of this map.
|
boolean |
containsKey(char k)
Checks whether the given value is contained in
AbstractChar2CharMap.keySet() . |
boolean |
containsValue(char v)
Checks whether the given value is contained in
AbstractChar2CharMap.values() . |
char |
get(char k)
Returns the value to which the given key is mapped.
|
Character |
get(Character ok) |
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() |
CharSet |
keySet()
Returns a type-specific-set view of the keys of this map.
|
Character |
put(Character ok,
Character ov)
Delegates to the corresponding type-specific method, taking care of returning
null on a missing key. |
char |
put(char k,
char v)
Adds a pair to the map.
|
boolean |
rehash()
Deprecated.
A no-op.
|
char |
remove(char k)
Removes the mapping with the given key.
|
Character |
remove(Object ok)
Delegates to the corresponding type-specific method, taking care of returning
null on a missing key. |
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.
|
CharCollection |
values()
Returns a type-specific-set view of the values of this map.
|
containsValue, entrySet, equals, putAll, toString
containsKey, defaultReturnValue, defaultReturnValue, get
defaultReturnValue, defaultReturnValue
containsKey, get
containsKey, get
public Char2CharOpenHashMap(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 Char2CharOpenHashMap(int expected)
Hash.DEFAULT_LOAD_FACTOR
as load factor.expected
- the expected number of elements in the hash map.public Char2CharOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.public Char2CharOpenHashMap(Map<? extends Character,? extends Character> m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Char2CharOpenHashMap(Map<? extends Character,? extends Character> m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.m
- a Map
to be copied into the new hash map.public Char2CharOpenHashMap(Char2CharMap m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Char2CharOpenHashMap(Char2CharMap 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 Char2CharOpenHashMap(char[] k, char[] 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 Char2CharOpenHashMap(char[] k, char[] 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 char put(char k, char v)
Char2CharFunction
put
in interface Char2CharFunction
put
in class AbstractChar2CharFunction
k
- the key.v
- the value.Function.put(Object,Object)
public Character put(Character ok, Character ov)
AbstractChar2CharFunction
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.
put
in interface Function<Character,Character>
put
in interface Map<Character,Character>
put
in class AbstractChar2CharFunction
ok
- the key.ov
- the value.null
if no value was present for the given key.Map.put(Object,Object)
public char remove(char k)
Char2CharFunction
remove
in interface Char2CharFunction
remove
in class AbstractChar2CharFunction
Function.remove(Object)
public Character remove(Object ok)
AbstractChar2CharFunction
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.
public char get(char k)
Char2CharFunction
get
in interface Char2CharFunction
k
- the key.Function.get(Object)
public boolean containsKey(char k)
AbstractChar2CharMap
AbstractChar2CharMap.keySet()
.containsKey
in interface Char2CharFunction
containsKey
in class AbstractChar2CharMap
Function.containsKey(Object)
public boolean containsValue(char v)
AbstractChar2CharMap
AbstractChar2CharMap.values()
.containsValue
in interface Char2CharMap
containsValue
in class AbstractChar2CharMap
Map.containsValue(Object)
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 Char2CharMap.FastEntrySet char2CharEntrySet()
Char2CharMap
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Char2CharMap.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).
char2CharEntrySet
in interface Char2CharMap
Char2CharMap.entrySet()
public CharSet keySet()
AbstractChar2CharMap
The view is backed by the set returned by AbstractChar2CharMap.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 Char2CharMap
keySet
in interface Map<Character,Character>
keySet
in class AbstractChar2CharMap
Map.keySet()
public CharCollection values()
AbstractChar2CharMap
The view is backed by the set returned by AbstractChar2CharMap.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 Char2CharMap
values
in interface Map<Character,Character>
values
in class AbstractChar2CharMap
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 Char2CharOpenHashMap 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.