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java.lang.Objectit.unimi.dsi.fastutil.shorts.AbstractShort2ByteFunction
it.unimi.dsi.fastutil.shorts.AbstractShort2ByteMap
it.unimi.dsi.fastutil.shorts.Short2ByteOpenHashMap
public class Short2ByteOpenHashMap
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 serialized:
deserialized tables gets the default growth factor).
Hash
,
HashCommon
,
Serialized FormNested Class Summary |
---|
Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.shorts.AbstractShort2ByteMap |
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AbstractShort2ByteMap.BasicEntry |
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash |
---|
Hash.Strategy<K> |
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.shorts.Short2ByteMap |
---|
Short2ByteMap.Entry, Short2ByteMap.FastEntrySet |
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 | |
---|---|
Short2ByteOpenHashMap()
Creates a new hash map with Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Short2ByteOpenHashMap(int n)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Short2ByteOpenHashMap(int n,
float f)
Creates a new hash map. |
|
Short2ByteOpenHashMap(Map<? extends Short,? extends Byte> m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
|
Short2ByteOpenHashMap(Map<? extends Short,? extends Byte> m,
float f)
Creates a new hash map copying a given one. |
|
Short2ByteOpenHashMap(short[] k,
byte[] v)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
|
Short2ByteOpenHashMap(short[] k,
byte[] v,
float f)
Creates a new hash map using the elements of two parallel arrays. |
|
Short2ByteOpenHashMap(Short2ByteMap m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
|
Short2ByteOpenHashMap(Short2ByteMap 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). |
Object |
clone()
Returns a deep copy of this map. |
boolean |
containsKey(short k)
Checks whether the given value is contained in AbstractShort2ByteMap.keySet() . |
boolean |
containsValue(byte v)
Checks whether the given value is contained in AbstractShort2ByteMap.values() . |
byte |
get(short k)
Returns the value to which the given key is mapped. |
Byte |
get(Short 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()
|
ShortSet |
keySet()
Returns a type-specific-set view of the keys of this map. |
byte |
put(short k,
byte v)
Adds a pair to the map. |
Byte |
put(Short ok,
Byte ov)
Delegates to the corresponding type-specific method, taking care of returning null on a missing key. |
boolean |
rehash()
Rehashes this map without changing the table size. |
Byte |
remove(Object ok)
Delegates to the corresponding type-specific method, taking care of returning null on a missing key. |
byte |
remove(short k)
Removes the mapping with the given key. |
Short2ByteMap.FastEntrySet |
short2ByteEntrySet()
Returns a type-specific set view of the mappings contained in this map. |
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. |
ByteCollection |
values()
Returns a type-specific-set view of the values of this map. |
Methods inherited from class it.unimi.dsi.fastutil.shorts.AbstractShort2ByteMap |
---|
containsValue, entrySet, equals, putAll, toString |
Methods inherited from class it.unimi.dsi.fastutil.shorts.AbstractShort2ByteFunction |
---|
containsKey, defaultReturnValue, defaultReturnValue, get |
Methods inherited from class java.lang.Object |
---|
getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface it.unimi.dsi.fastutil.shorts.Short2ByteFunction |
---|
defaultReturnValue, defaultReturnValue |
Methods inherited from interface it.unimi.dsi.fastutil.Function |
---|
containsKey, get |
Methods inherited from interface java.util.Map |
---|
containsKey, get |
Field Detail |
---|
public static final long serialVersionUID
Constructor Detail |
---|
public Short2ByteOpenHashMap(int n, float f)
n
/f
.
n
- the expected number of elements in the hash map.f
- the load factor.Hash.PRIMES
public Short2ByteOpenHashMap(int n)
Hash.DEFAULT_LOAD_FACTOR
as load factor.
n
- the expected number of elements in the hash map.public Short2ByteOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.
public Short2ByteOpenHashMap(Map<? extends Short,? extends Byte> m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Short2ByteOpenHashMap(Map<? extends Short,? extends Byte> m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.
m
- a Map
to be copied into the new hash map.public Short2ByteOpenHashMap(Short2ByteMap m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Short2ByteOpenHashMap(Short2ByteMap 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 Short2ByteOpenHashMap(short[] k, byte[] 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 Short2ByteOpenHashMap(short[] k, byte[] 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.Method Detail |
---|
public void growthFactor(int growthFactor)
growthFactor
- the new growth factor; it must be positive.public int growthFactor()
growthFactor(int)
public byte put(short k, byte v)
Short2ByteFunction
put
in interface Short2ByteFunction
put
in class AbstractShort2ByteFunction
k
- the key.v
- the value.
Function.put(Object,Object)
public Byte put(Short ok, Byte ov)
AbstractShort2ByteFunction
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<Short,Byte>
put
in interface Map<Short,Byte>
put
in class AbstractShort2ByteFunction
ok
- the key.ov
- the value.
null
if no value was present for the given key.Map.put(Object,Object)
public boolean containsValue(byte v)
AbstractShort2ByteMap
AbstractShort2ByteMap.values()
.
containsValue
in interface Short2ByteMap
containsValue
in class AbstractShort2ByteMap
Map.containsValue(Object)
public void clear()
Function
clear
in interface Function<Short,Byte>
clear
in interface Map<Short,Byte>
clear
in class AbstractShort2ByteFunction
Map.clear()
public boolean containsKey(short k)
AbstractShort2ByteMap
AbstractShort2ByteMap.keySet()
.
containsKey
in interface Short2ByteFunction
containsKey
in class AbstractShort2ByteMap
Function.containsKey(Object)
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.
size
in interface Function<Short,Byte>
size
in interface Map<Short,Byte>
public boolean isEmpty()
isEmpty
in interface Map<Short,Byte>
isEmpty
in class AbstractShort2ByteMap
public byte get(short k)
Short2ByteFunction
get
in interface Short2ByteFunction
k
- the key.
Function.get(Object)
public byte remove(short k)
Short2ByteFunction
remove
in interface Short2ByteFunction
remove
in class AbstractShort2ByteFunction
Function.remove(Object)
public Byte get(Short ok)
public Byte remove(Object ok)
AbstractShort2ByteFunction
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.
remove
in interface Function<Short,Byte>
remove
in interface Map<Short,Byte>
remove
in class AbstractShort2ByteFunction
null
if no value was present for the given key.Map.remove(Object)
public Short2ByteMap.FastEntrySet short2ByteEntrySet()
Short2ByteMap
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Short2ByteMap.entrySet()
so that it returns an ObjectSet
of objects of type Short2ByteMap.Entry
(the latter makes it possible to
access keys and values with type-specific methods).
short2ByteEntrySet
in interface Short2ByteMap
Short2ByteMap.entrySet()
public ShortSet keySet()
AbstractShort2ByteMap
The view is backed by the set returned by AbstractShort2ByteMap.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 Short2ByteMap
keySet
in interface Map<Short,Byte>
keySet
in class AbstractShort2ByteMap
Map.keySet()
public ByteCollection values()
AbstractShort2ByteMap
The view is backed by the set returned by AbstractShort2ByteMap.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 Short2ByteMap
values
in interface Map<Short,Byte>
values
in class AbstractShort2ByteMap
Map.values()
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 optimize 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
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()
,
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.
clone
in class 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.
hashCode
in interface Map<Short,Byte>
hashCode
in class AbstractShort2ByteMap
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