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java.lang.Objectit.unimi.dsi.fastutil.bytes.AbstractByte2ReferenceFunction<V>
it.unimi.dsi.fastutil.bytes.AbstractByte2ReferenceMap<V>
it.unimi.dsi.fastutil.bytes.Byte2ReferenceOpenHashMap<V>
public class Byte2ReferenceOpenHashMap<V>
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 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 FormNested Class Summary |
---|
Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.bytes.AbstractByte2ReferenceMap |
---|
AbstractByte2ReferenceMap.BasicEntry<V> |
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash |
---|
Hash.Strategy<K> |
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.bytes.Byte2ReferenceMap |
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Byte2ReferenceMap.Entry<V>, Byte2ReferenceMap.FastEntrySet<V> |
Field Summary | |
---|---|
protected Byte2ReferenceMap.FastEntrySet<V> |
entries
Cached set of entries. |
protected float |
f
The acceptable load factor. |
protected byte[] |
key
The array of keys. |
protected ByteSet |
keys
Cached set of keys. |
protected int |
mask
The mask for wrapping a position counter. |
protected int |
maxFill
Threshold after which we rehash. |
protected int |
n
The current table size. |
static long |
serialVersionUID
|
protected int |
size
Number of entries in the set. |
protected boolean[] |
used
The array telling whether a position is used. |
protected V[] |
value
The array of values. |
protected ReferenceCollection<V> |
values
Cached collection of values. |
Fields inherited from class it.unimi.dsi.fastutil.bytes.AbstractByte2ReferenceFunction |
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defRetValue |
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 | |
---|---|
Byte2ReferenceOpenHashMap()
Creates a new hash map with initial expected Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Byte2ReferenceOpenHashMap(byte[] k,
V[] v)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
|
Byte2ReferenceOpenHashMap(byte[] k,
V[] v,
float f)
Creates a new hash map using the elements of two parallel arrays. |
|
Byte2ReferenceOpenHashMap(Byte2ReferenceMap<V> m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
|
Byte2ReferenceOpenHashMap(Byte2ReferenceMap<V> m,
float f)
Creates a new hash map copying a given type-specific one. |
|
Byte2ReferenceOpenHashMap(int expected)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Byte2ReferenceOpenHashMap(int expected,
float f)
Creates a new hash map. |
|
Byte2ReferenceOpenHashMap(Map<? extends Byte,? extends V> m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
|
Byte2ReferenceOpenHashMap(Map<? extends Byte,? extends V> m,
float f)
Creates a new hash map copying a given one. |
Method Summary | |
---|---|
Byte2ReferenceMap.FastEntrySet<V> |
byte2ReferenceEntrySet()
Returns a type-specific set view of the mappings contained in this map. |
void |
clear()
Removes all associations from this function (optional operation). |
Byte2ReferenceOpenHashMap<V> |
clone()
Returns a deep copy of this map. |
boolean |
containsKey(byte k)
Checks whether the given value is contained in AbstractByte2ReferenceMap.keySet() . |
boolean |
containsValue(Object v)
Checks whether the given value is contained in AbstractByte2ReferenceMap.values() . |
V |
get(byte k)
Returns the value to which the given key is mapped. |
V |
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. |
V |
put(byte k,
V v)
Adds a pair to the map. |
V |
put(Byte ok,
V ov)
Delegates to the corresponding type-specific method, taking care of returning null on a missing key. |
boolean |
rehash()
Deprecated. A no-op. |
protected void |
rehash(int newN)
Resizes the map. |
V |
remove(byte k)
Removes the mapping with the given key. |
V |
remove(Object ok)
Delegates to the corresponding type-specific method, taking care of returning null on a missing key. |
protected int |
shiftKeys(int pos)
Shifts left entries with the specified hash code, starting at the specified position, and empties the resulting free entry. |
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. |
ReferenceCollection<V> |
values()
Returns a type-specific-set view of the values of this map. |
Methods inherited from class it.unimi.dsi.fastutil.bytes.AbstractByte2ReferenceMap |
---|
entrySet, equals, putAll, toString |
Methods inherited from class it.unimi.dsi.fastutil.bytes.AbstractByte2ReferenceFunction |
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containsKey, defaultReturnValue, defaultReturnValue, get |
Methods inherited from class java.lang.Object |
---|
finalize, getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface it.unimi.dsi.fastutil.bytes.Byte2ReferenceFunction |
---|
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
protected transient byte[] key
protected transient V[] value
protected transient boolean[] used
protected final float f
protected transient int n
protected transient int maxFill
f
.
protected transient int mask
protected int size
protected transient volatile Byte2ReferenceMap.FastEntrySet<V> entries
protected transient volatile ByteSet keys
protected transient volatile ReferenceCollection<V> values
Constructor Detail |
---|
public Byte2ReferenceOpenHashMap(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 Byte2ReferenceOpenHashMap(int expected)
Hash.DEFAULT_LOAD_FACTOR
as load factor.
expected
- the expected number of elements in the hash map.public Byte2ReferenceOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.
public Byte2ReferenceOpenHashMap(Map<? extends Byte,? extends V> m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Byte2ReferenceOpenHashMap(Map<? extends Byte,? extends V> m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.
m
- a Map
to be copied into the new hash map.public Byte2ReferenceOpenHashMap(Byte2ReferenceMap<V> m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Byte2ReferenceOpenHashMap(Byte2ReferenceMap<V> 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 Byte2ReferenceOpenHashMap(byte[] k, V[] 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 Byte2ReferenceOpenHashMap(byte[] k, V[] 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 V put(byte k, V v)
Byte2ReferenceFunction
put
in interface Byte2ReferenceFunction<V>
put
in class AbstractByte2ReferenceFunction<V>
k
- the key.v
- the value.
Function.put(Object,Object)
public V put(Byte ok, V ov)
AbstractByte2ReferenceFunction
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<Byte,V>
put
in interface Map<Byte,V>
put
in class AbstractByte2ReferenceFunction<V>
ok
- the key.ov
- the value.
null
if no value was present for the given key.Map.put(Object,Object)
protected final int shiftKeys(int pos)
pos
- a starting position.
public V remove(byte k)
Byte2ReferenceFunction
remove
in interface Byte2ReferenceFunction<V>
remove
in class AbstractByte2ReferenceFunction<V>
Function.remove(Object)
public V remove(Object ok)
AbstractByte2ReferenceFunction
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<Byte,V>
remove
in interface Map<Byte,V>
remove
in class AbstractByte2ReferenceFunction<V>
null
if no value was present for the given key.Map.remove(Object)
public V get(Byte ok)
public V get(byte k)
Byte2ReferenceFunction
get
in interface Byte2ReferenceFunction<V>
k
- the key.
Function.get(Object)
public boolean containsKey(byte k)
AbstractByte2ReferenceMap
AbstractByte2ReferenceMap.keySet()
.
containsKey
in interface Byte2ReferenceFunction<V>
containsKey
in class AbstractByte2ReferenceMap<V>
Function.containsKey(Object)
public boolean containsValue(Object v)
AbstractByte2ReferenceMap
AbstractByte2ReferenceMap.values()
.
containsValue
in interface Map<Byte,V>
containsValue
in class AbstractByte2ReferenceMap<V>
public void clear()
Function
clear
in interface Function<Byte,V>
clear
in interface Map<Byte,V>
clear
in class AbstractByte2ReferenceFunction<V>
Map.clear()
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<Byte,V>
size
in interface Map<Byte,V>
public boolean isEmpty()
isEmpty
in interface Map<Byte,V>
isEmpty
in class AbstractByte2ReferenceMap<V>
@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 Byte2ReferenceMap.FastEntrySet<V> byte2ReferenceEntrySet()
Byte2ReferenceMap
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Byte2ReferenceMap.entrySet()
so that it returns an ObjectSet
of objects of type Byte2ReferenceMap.Entry
(the latter makes it possible to
access keys and values with type-specific methods).
byte2ReferenceEntrySet
in interface Byte2ReferenceMap<V>
Byte2ReferenceMap.entrySet()
public ByteSet keySet()
AbstractByte2ReferenceMap
The view is backed by the set returned by AbstractByte2ReferenceMap.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 Byte2ReferenceMap<V>
keySet
in interface Map<Byte,V>
keySet
in class AbstractByte2ReferenceMap<V>
Map.keySet()
public ReferenceCollection<V> values()
AbstractByte2ReferenceMap
The view is backed by the set returned by AbstractByte2ReferenceMap.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 Byte2ReferenceMap<V>
values
in interface Map<Byte,V>
values
in class AbstractByte2ReferenceMap<V>
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()
protected void rehash(int newN)
This method implements the basic rehashing strategy, and may be overriden by subclasses implementing different rehashing strategies (e.g., disk-based rehashing). However, you should not override this method unless you understand the internal workings of this class.
newN
- the new sizepublic Byte2ReferenceOpenHashMap<V> 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<Byte,V>
hashCode
in class AbstractByte2ReferenceMap<V>
|
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