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java.lang.Objectit.unimi.dsi.fastutil.chars.AbstractChar2ShortMap
it.unimi.dsi.fastutil.chars.Char2ShortOpenHashMap
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
enlarged as needed 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.
The enlargement speed is controlled by the growth factor, a
positive number. If the growth factor is p, then the table is
enlarged each time roughly by a factor 2p/16. By default, p is
Hash.DEFAULT_GROWTH_FACTOR
, which means that the table is doubled at
each enlargement, but one can easily set more or less aggressive policies by
calling growthFactor(int)
(note that the growth factor is not serialised:
deserialised tables gets the default growth factor).
Hash
,
HashCommon
,
Serialized FormField Summary | |
static long |
serialVersionUID
|
Fields inherited from interface it.unimi.dsi.fastutil.Hash |
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED |
Constructor Summary | |
Char2ShortOpenHashMap()
Creates a new hash map with Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Char2ShortOpenHashMap(Char2ShortMap m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
|
Char2ShortOpenHashMap(Char2ShortMap m,
float f)
Creates a new hash map copying a given type-specific one. |
|
Char2ShortOpenHashMap(int n)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Char2ShortOpenHashMap(int n,
float f)
Creates a new hash map. |
|
Char2ShortOpenHashMap(Map m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
|
Char2ShortOpenHashMap(Map m,
float f)
Creates a new hash map copying a given one. |
Method Summary | |
void |
clear()
|
Object |
clone()
Returns a deep copy of this map. |
boolean |
containsKey(char k)
|
boolean |
containsValue(short v)
|
Set |
entrySet()
|
short |
get(char k)
Returns the value to which the given key is mapped. |
Object |
get(Object ok)
|
int |
growthFactor()
Gets the growth factor. |
void |
growthFactor(int growthFactor)
Sets the growth factor. |
int |
hashCode()
Returns a hash code for this map. |
boolean |
isEmpty()
|
Set |
keySet()
|
short |
put(char k,
short v)
Adds a pair to the map. |
Object |
put(Object ok,
Object ov)
|
boolean |
rehash()
Rehashes this map without changing the table size. |
short |
remove(char k)
Removes the mapping with the given key. |
Object |
remove(Object ok)
|
int |
size()
|
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. |
Collection |
values()
|
Methods inherited from class it.unimi.dsi.fastutil.chars.AbstractChar2ShortMap |
containsKey, containsValue, defaultReturnValue, defaultReturnValue, equals, getDefRetValue, putAll, setDefRetValue, toString |
Methods inherited from class java.lang.Object |
getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface it.unimi.dsi.fastutil.chars.Char2ShortMap |
defaultReturnValue, defaultReturnValue, getDefRetValue, setDefRetValue |
Methods inherited from interface java.util.Map |
containsKey, containsValue, equals, putAll |
Field Detail |
public static final long serialVersionUID
Constructor Detail |
public Char2ShortOpenHashMap(int n, float f)
n
/f
.
n
- the expected number of elements in the hash map.f
- the load factor.Hash.PRIMES
public Char2ShortOpenHashMap(int n)
Hash.DEFAULT_LOAD_FACTOR
as load factor.
n
- the expected number of elements in the hash map.public Char2ShortOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.
public Char2ShortOpenHashMap(Map m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Char2ShortOpenHashMap(Map m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.
m
- a Map
to be copied into the new hash map.public Char2ShortOpenHashMap(Char2ShortMap m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Char2ShortOpenHashMap(Char2ShortMap 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.Method Detail |
public void growthFactor(int growthFactor)
growthFactor
- the new growth factor; it must be positive.public int growthFactor()
public Object put(Object ok, Object ov)
put
in interface Map
public short put(char k, short v)
Char2ShortMap
put
in interface Char2ShortMap
k
- the key.v
- the value.
Map.put(Object,Object)
public Object remove(Object ok)
remove
in interface Map
public boolean containsValue(short v)
containsValue
in interface Char2ShortMap
Map.containsValue(Object)
public void clear()
clear
in interface Map
public boolean containsKey(char k)
containsKey
in interface Char2ShortMap
Map.containsKey(Object)
public int size()
size
in interface Map
public boolean isEmpty()
isEmpty
in interface Map
public Object get(Object ok)
get
in interface Map
public short get(char k)
Char2ShortMap
get
in interface Char2ShortMap
k
- the key.
Map.get(Object)
public short remove(char k)
Char2ShortMap
remove
in interface Char2ShortMap
k
-
Map.remove(Object)
public Set entrySet()
entrySet
in interface Map
public Set keySet()
keySet
in interface Map
public Collection values()
values
in interface Map
public boolean rehash()
This method should be called when the map underwent numerous deletions and insertions. In this case, free entries become rare, and unsuccessful searches require probing all entries. For reasonable load factors this method is linear in the number of entries. You will need as much additional free memory as that occupied by the table.
If you need to reduce the table siza to fit exactly
this map, you must use trim()
.
true
if there was enough memory to rehash the map, false
otherwise.trim()
public boolean trim()
This method rehashes to the smallest size satisfying the load factor. It can be used when the map will not be changed anymore, so to optimise access speed (by collecting deleted entries) and size.
If the table size is already the minimum possible, this method
does nothing. If you want to guarantee rehashing, use rehash()
.
trim(int)
,
rehash()
public boolean trim(int n)
Let N be the smallest table size that can hold
n
entries, still satisfying the load factor. If the current
table size is smaller than or equal to N, or if the number of
elements of this map is larger than 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.
n
- the threshold for the trimming.
trim()
,
rehash()
public Object 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.
hashCode
in interface Map
hashCode
in class AbstractChar2ShortMap
|
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