public class Object2ByteOpenCustomHashMap<K> extends AbstractObject2ByteMap<K> 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 FormAbstractObject2ByteMap.BasicEntry<K>
Hash.Strategy<K>
Object2ByteMap.Entry<K>, Object2ByteMap.FastEntrySet<K>
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
Constructor and Description |
---|
Object2ByteOpenCustomHashMap(Hash.Strategy<K> strategy)
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
Object2ByteOpenCustomHashMap(int expected,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map.
|
Object2ByteOpenCustomHashMap(int expected,
Hash.Strategy<K> strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Object2ByteOpenCustomHashMap(K[] k,
byte[] v,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map using the elements of two parallel arrays.
|
Object2ByteOpenCustomHashMap(K[] k,
byte[] v,
Hash.Strategy<K> strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
Object2ByteOpenCustomHashMap(Map<? extends K,? extends Byte> m,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map copying a given one.
|
Object2ByteOpenCustomHashMap(Map<? extends K,? extends Byte> m,
Hash.Strategy<K> strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
Object2ByteOpenCustomHashMap(Object2ByteMap<K> m,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map copying a given type-specific one.
|
Object2ByteOpenCustomHashMap(Object2ByteMap<K> m,
Hash.Strategy<K> strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
Modifier and Type | Method and Description |
---|---|
byte |
add(K 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(K k,
byte incr)
Adds an increment to value currently associated with a key.
|
void |
clear()
Removes all associations from this function (optional operation).
|
Object2ByteOpenCustomHashMap<K> |
clone()
Returns a deep copy of this map.
|
boolean |
containsKey(Object k)
Checks whether the given value is contained in
AbstractObject2ByteMap.keySet() . |
boolean |
containsValue(byte v)
Checks whether the given value is contained in
AbstractObject2ByteMap.values() . |
byte |
getByte(Object k)
Returns the value to which the given key is mapped.
|
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() |
ObjectSet<K> |
keySet()
Returns a type-specific-set view of the keys of this map.
|
Object2ByteMap.FastEntrySet<K> |
object2ByteEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
byte |
put(K k,
byte v)
Adds a pair to the map.
|
Byte |
put(K 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(Object ok)
Delegates to the corresponding type-specific method, taking care of returning
null on a missing key. |
byte |
removeByte(Object k)
Removes the mapping with the given key.
|
int |
size()
Returns the intended number of keys in this function, or -1 if no such number exists.
|
Hash.Strategy<K> |
strategy()
Returns the hashing strategy.
|
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
defaultReturnValue, defaultReturnValue, get
defaultReturnValue, defaultReturnValue
public Object2ByteOpenCustomHashMap(int expected, float f, Hash.Strategy<K> strategy)
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.strategy
- the strategy.public Object2ByteOpenCustomHashMap(int expected, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor.expected
- the expected number of elements in the hash map.strategy
- the strategy.public Object2ByteOpenCustomHashMap(Hash.Strategy<K> strategy)
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.strategy
- the strategy.public Object2ByteOpenCustomHashMap(Map<? extends K,? extends Byte> m, float f, Hash.Strategy<K> strategy)
m
- a Map
to be copied into the new hash map.f
- the load factor.strategy
- the strategy.public Object2ByteOpenCustomHashMap(Map<? extends K,? extends Byte> m, Hash.Strategy<K> strategy)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.m
- a Map
to be copied into the new hash map.strategy
- the strategy.public Object2ByteOpenCustomHashMap(Object2ByteMap<K> m, float f, Hash.Strategy<K> strategy)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.strategy
- the strategy.public Object2ByteOpenCustomHashMap(Object2ByteMap<K> m, Hash.Strategy<K> strategy)
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.strategy
- the strategy.public Object2ByteOpenCustomHashMap(K[] k, byte[] v, float f, Hash.Strategy<K> strategy)
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.strategy
- the strategy.IllegalArgumentException
- if k
and v
have different lengths.public Object2ByteOpenCustomHashMap(K[] k, byte[] v, Hash.Strategy<K> strategy)
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.strategy
- the strategy.IllegalArgumentException
- if k
and v
have different lengths.public Hash.Strategy<K> strategy()
public byte put(K k, byte v)
Object2ByteFunction
put
in interface Object2ByteFunction<K>
put
in class AbstractObject2ByteFunction<K>
k
- the key.v
- the value.Function.put(Object,Object)
public Byte put(K ok, Byte ov)
AbstractObject2ByteFunction
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(K 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(K 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 removeByte(Object k)
Object2ByteFunction
removeByte
in interface Object2ByteFunction<K>
removeByte
in class AbstractObject2ByteFunction<K>
Function.remove(Object)
public Byte remove(Object ok)
AbstractObject2ByteFunction
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 getByte(Object k)
Object2ByteFunction
getByte
in interface Object2ByteFunction<K>
k
- the key.Function.get(Object)
public boolean containsKey(Object k)
AbstractObject2ByteMap
AbstractObject2ByteMap.keySet()
.containsKey
in interface Function<K,Byte>
containsKey
in interface Map<K,Byte>
containsKey
in class AbstractObject2ByteMap<K>
k
- the key.key
.Map.containsKey(Object)
public boolean containsValue(byte v)
AbstractObject2ByteMap
AbstractObject2ByteMap.values()
.containsValue
in interface Object2ByteMap<K>
containsValue
in class AbstractObject2ByteMap<K>
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 Object2ByteMap.FastEntrySet<K> object2ByteEntrySet()
Object2ByteMap
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Object2ByteMap.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).
object2ByteEntrySet
in interface Object2ByteMap<K>
Object2ByteMap.entrySet()
public ObjectSet<K> keySet()
AbstractObject2ByteMap
The view is backed by the set returned by AbstractObject2ByteMap.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 Object2ByteMap<K>
keySet
in interface Map<K,Byte>
keySet
in class AbstractObject2ByteMap<K>
Map.keySet()
public ByteCollection values()
AbstractObject2ByteMap
The view is backed by the set returned by AbstractObject2ByteMap.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 Object2ByteMap<K>
values
in interface Map<K,Byte>
values
in class AbstractObject2ByteMap<K>
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 Object2ByteOpenCustomHashMap<K> 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.