public class Byte2ByteOpenHashMap extends AbstractByte2ByteMap 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 FormAbstractByte2ByteMap.BasicEntry
Hash.Strategy<K>
Byte2ByteMap.Entry, Byte2ByteMap.FastEntrySet
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
Constructor and Description |
---|
Byte2ByteOpenHashMap()
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
Byte2ByteOpenHashMap(byte[] k,
byte[] v)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
Byte2ByteOpenHashMap(byte[] k,
byte[] v,
float f)
Creates a new hash map using the elements of two parallel arrays.
|
Byte2ByteOpenHashMap(Byte2ByteMap m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
Byte2ByteOpenHashMap(Byte2ByteMap m,
float f)
Creates a new hash map copying a given type-specific one.
|
Byte2ByteOpenHashMap(int expected)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Byte2ByteOpenHashMap(int expected,
float f)
Creates a new hash map.
|
Byte2ByteOpenHashMap(Map<? extends Byte,? extends Byte> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
Byte2ByteOpenHashMap(Map<? extends Byte,? extends Byte> m,
float f)
Creates a new hash map copying a given one.
|
Modifier and Type | Method and Description |
---|---|
byte |
add(byte k,
byte incr)
Deprecated.
use
addTo() instead; having the same name of a Set method turned out to be a recipe for disaster. |
byte |
addTo(byte k,
byte incr)
Adds an increment to value currently associated with a key.
|
Byte2ByteMap.FastEntrySet |
byte2ByteEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
void |
clear()
Removes all associations from this function (optional operation).
|
Byte2ByteOpenHashMap |
clone()
Returns a deep copy of this map.
|
boolean |
containsKey(byte k)
Checks whether the given value is contained in
AbstractByte2ByteMap.keySet() . |
boolean |
containsValue(byte v)
Checks whether the given value is contained in
AbstractByte2ByteMap.values() . |
byte |
get(byte k)
Returns the value to which the given key is mapped.
|
Byte |
get(Byte 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() |
ByteSet |
keySet()
Returns a type-specific-set view of the keys of this map.
|
byte |
put(byte k,
byte v)
Adds a pair to the map.
|
Byte |
put(Byte ok,
Byte ov)
Delegates to the corresponding type-specific method, taking care of returning
null on a missing key. |
boolean |
rehash()
Deprecated.
A no-op.
|
byte |
remove(byte k)
Removes the mapping with the given key.
|
Byte |
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.
|
ByteCollection |
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 Byte2ByteOpenHashMap(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 Byte2ByteOpenHashMap(int expected)
Hash.DEFAULT_LOAD_FACTOR
as load factor.expected
- the expected number of elements in the hash map.public Byte2ByteOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.public Byte2ByteOpenHashMap(Map<? extends Byte,? extends Byte> m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Byte2ByteOpenHashMap(Map<? extends Byte,? 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 Byte2ByteOpenHashMap(Byte2ByteMap m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Byte2ByteOpenHashMap(Byte2ByteMap 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 Byte2ByteOpenHashMap(byte[] 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 Byte2ByteOpenHashMap(byte[] 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.public byte put(byte k, byte v)
Byte2ByteFunction
put
in interface Byte2ByteFunction
put
in class AbstractByte2ByteFunction
k
- the key.v
- the value.Function.put(Object,Object)
public Byte put(Byte ok, Byte ov)
AbstractByte2ByteFunction
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.
@Deprecated public byte add(byte k, byte incr)
addTo()
instead; having the same name of a Set
method turned out to be a recipe for disaster.k
- the key.incr
- the increment.public byte addTo(byte k, byte incr)
Note that this method respects the default return value semantics: when called with a key that does not currently appears in the map, the key will be associated with the default return value plus the given increment.
k
- the key.incr
- the increment.public byte remove(byte k)
Byte2ByteFunction
remove
in interface Byte2ByteFunction
remove
in class AbstractByte2ByteFunction
Function.remove(Object)
public Byte remove(Object ok)
AbstractByte2ByteFunction
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 byte get(byte k)
Byte2ByteFunction
get
in interface Byte2ByteFunction
k
- the key.Function.get(Object)
public boolean containsKey(byte k)
AbstractByte2ByteMap
AbstractByte2ByteMap.keySet()
.containsKey
in interface Byte2ByteFunction
containsKey
in class AbstractByte2ByteMap
Function.containsKey(Object)
public boolean containsValue(byte v)
AbstractByte2ByteMap
AbstractByte2ByteMap.values()
.containsValue
in interface Byte2ByteMap
containsValue
in class AbstractByte2ByteMap
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 Byte2ByteMap.FastEntrySet byte2ByteEntrySet()
Byte2ByteMap
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Byte2ByteMap.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).
byte2ByteEntrySet
in interface Byte2ByteMap
Byte2ByteMap.entrySet()
public ByteSet keySet()
AbstractByte2ByteMap
The view is backed by the set returned by AbstractByte2ByteMap.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 Byte2ByteMap
keySet
in interface Map<Byte,Byte>
keySet
in class AbstractByte2ByteMap
Map.keySet()
public ByteCollection values()
AbstractByte2ByteMap
The view is backed by the set returned by AbstractByte2ByteMap.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 Byte2ByteMap
values
in interface Map<Byte,Byte>
values
in class AbstractByte2ByteMap
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 Byte2ByteOpenHashMap 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.