public class Byte2ObjectOpenCustomHashMap<V> extends AbstractByte2ObjectMap<V> implements Serializable, Cloneable, Hash
Instances of this class use a hash table to represent a map. The table is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size; however, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create maps with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.
Note that clear() does not modify the hash table size.
Rather, a family of trimming
methods lets you control the size of the table; this is particularly useful
if you reuse instances of this class.
Hash,
HashCommon,
Serialized FormAbstractByte2ObjectMap.BasicEntry<V>, AbstractByte2ObjectMap.BasicEntrySet<V>Hash.Strategy<K>Byte2ObjectMap.Entry<V>, Byte2ObjectMap.FastEntrySet<V>| Modifier and Type | Field and Description |
|---|---|
protected boolean |
containsNullKey
Whether this map contains the key zero.
|
protected Byte2ObjectMap.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 |
minN
We never resize below this threshold, which is the construction-time {#n}.
|
protected int |
n
The current table size.
|
protected int |
size
Number of entries in the set (including the key zero, if present).
|
protected ByteHash.Strategy |
strategy
The hash strategy of this custom map.
|
protected V[] |
value
The array of values.
|
protected ObjectCollection<V> |
values
Cached collection of values.
|
defRetValueDEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR| Constructor and Description |
|---|
Byte2ObjectOpenCustomHashMap(byte[] k,
V[] v,
ByteHash.Strategy strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
Byte2ObjectOpenCustomHashMap(byte[] k,
V[] v,
float f,
ByteHash.Strategy strategy)
Creates a new hash map using the elements of two parallel arrays.
|
Byte2ObjectOpenCustomHashMap(Byte2ObjectMap<V> m,
ByteHash.Strategy strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
Byte2ObjectOpenCustomHashMap(Byte2ObjectMap<V> m,
float f,
ByteHash.Strategy strategy)
Creates a new hash map copying a given type-specific one.
|
Byte2ObjectOpenCustomHashMap(ByteHash.Strategy strategy)
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
Byte2ObjectOpenCustomHashMap(int expected,
ByteHash.Strategy strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Byte2ObjectOpenCustomHashMap(int expected,
float f,
ByteHash.Strategy strategy)
Creates a new hash map.
|
Byte2ObjectOpenCustomHashMap(Map<? extends Byte,? extends V> m,
ByteHash.Strategy strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
Byte2ObjectOpenCustomHashMap(Map<? extends Byte,? extends V> m,
float f,
ByteHash.Strategy strategy)
Creates a new hash map copying a given one.
|
| Modifier and Type | Method and Description |
|---|---|
Byte2ObjectMap.FastEntrySet<V> |
byte2ObjectEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
void |
clear()
Removes all of the mappings from this map (optional operation).
|
Byte2ObjectOpenCustomHashMap<V> |
clone()
Returns a deep copy of this map.
|
V |
compute(byte k,
BiFunction<? super Byte,? super V,? extends V> remappingFunction)
Attempts to compute a mapping for the specified key and its current mapped value (or
null if there is no current mapping). |
V |
computeIfAbsent(byte k,
IntFunction<? extends V> mappingFunction)
If the specified key is not already associated with a value, attempts to compute its value
using the given mapping function and enters it into this map.
|
V |
computeIfPresent(byte k,
BiFunction<? super Byte,? super V,? extends V> remappingFunction)
If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
|
boolean |
containsKey(byte k)
Returns true if this function contains a mapping for the specified key.
|
boolean |
containsValue(Object v) |
V |
get(byte k)
Returns the value to which the given key is mapped.
|
V |
getOrDefault(byte k,
V defaultValue)
Returns the value to which the specified key is mapped, or the
defaultValue if this
map contains no mapping for the key. |
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 |
merge(byte k,
V v,
BiFunction<? super V,? super V,? extends V> remappingFunction)
If the specified key is not already associated with a value or is associated with null, associates it with the given non-null
value. |
V |
put(byte k,
V v)
Adds a pair to the map (optional operation).
|
void |
putAll(Map<? extends Byte,? extends V> m) |
V |
putIfAbsent(byte k,
V v)
If the specified key is not already associated with a value, associates it with the given
value and returns the default return value, else returns
the current value.
|
protected void |
rehash(int newN)
Rehashes the map.
|
V |
remove(byte k)
Removes the mapping with the given key (optional operation).
|
boolean |
remove(byte k,
Object v)
Removes the entry for the specified key only if it is currently mapped to the specified value.
|
V |
replace(byte k,
V v)
Replaces the entry for the specified key only if it is currently mapped to some value.
|
boolean |
replace(byte k,
V oldValue,
V v)
Replaces the entry for the specified key only if currently mapped to the specified value.
|
protected void |
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 number of key/value mappings in this map.
|
ByteHash.Strategy |
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.
|
ObjectCollection<V> |
values()
Returns a type-specific-set view of the values of this map.
|
equals, toStringdefaultReturnValue, defaultReturnValuefinalize, getClass, notify, notifyAll, wait, wait, waitcompute, computeIfAbsent, computeIfAbsentPartial, computeIfPresent, containsKey, defaultReturnValue, defaultReturnValue, entrySet, get, getOrDefault, merge, put, putIfAbsent, remove, remove, replace, replaceapplyforEach, replaceAllprotected transient byte[] key
protected transient V[] value
protected transient int mask
protected transient boolean containsNullKey
protected ByteHash.Strategy strategy
protected transient int n
protected transient int maxFill
f.protected final transient int minN
protected int size
protected final float f
protected transient Byte2ObjectMap.FastEntrySet<V> entries
protected transient ByteSet keys
protected transient ObjectCollection<V> values
public Byte2ObjectOpenCustomHashMap(int expected,
float f,
ByteHash.Strategy 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 map.f - the load factor.strategy - the strategy.public Byte2ObjectOpenCustomHashMap(int expected,
ByteHash.Strategy strategy)
Hash.DEFAULT_LOAD_FACTOR as load factor.expected - the expected number of elements in the hash map.strategy - the strategy.public Byte2ObjectOpenCustomHashMap(ByteHash.Strategy strategy)
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor.strategy - the strategy.public Byte2ObjectOpenCustomHashMap(Map<? extends Byte,? extends V> m, float f, ByteHash.Strategy strategy)
m - a Map to be copied into the new hash map.f - the load factor.strategy - the strategy.public Byte2ObjectOpenCustomHashMap(Map<? extends Byte,? extends V> m, ByteHash.Strategy 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 Byte2ObjectOpenCustomHashMap(Byte2ObjectMap<V> m, float f, ByteHash.Strategy strategy)
m - a type-specific map to be copied into the new hash map.f - the load factor.strategy - the strategy.public Byte2ObjectOpenCustomHashMap(Byte2ObjectMap<V> m, ByteHash.Strategy 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 Byte2ObjectOpenCustomHashMap(byte[] k,
V[] v,
float f,
ByteHash.Strategy 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 Byte2ObjectOpenCustomHashMap(byte[] k,
V[] v,
ByteHash.Strategy 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 ByteHash.Strategy strategy()
public void putAll(Map<? extends Byte,? extends V> m)
AbstractByte2ObjectMappublic V put(byte k, V v)
Byte2ObjectFunctionput in interface Byte2ObjectFunction<V>k - the key.v - the value.Function.put(Object,Object)protected final void shiftKeys(int pos)
pos - a starting position.public V remove(byte k)
Byte2ObjectFunctionremove in interface Byte2ObjectFunction<V>k - the key.Function.remove(Object)public V get(byte k)
Byte2ObjectFunctionget in interface Byte2ObjectFunction<V>k - the key.Function.get(Object)public boolean containsKey(byte k)
Byte2ObjectMapcontainsKey in interface Byte2ObjectFunction<V>containsKey in interface Byte2ObjectMap<V>containsKey in class AbstractByte2ObjectMap<V>k - the key.key.Map.containsKey(Object)public boolean containsValue(Object v)
containsValue in interface Map<Byte,V>containsValue in class AbstractByte2ObjectMap<V>public V getOrDefault(byte k, V defaultValue)
defaultValue if this
map contains no mapping for the key.getOrDefault in interface Byte2ObjectMap<V>k - the key.defaultValue - the default mapping of the key.defaultValue if this map contains no mapping for the key.Map.getOrDefault(Object, Object)public V putIfAbsent(byte k, V v)
putIfAbsent in interface Byte2ObjectMap<V>k - key with which the specified value is to be associated.v - value to be associated with the specified key.Map.putIfAbsent(Object, Object)public boolean remove(byte k,
Object v)
remove in interface Byte2ObjectMap<V>k - key with which the specified value is associated.v - value expected to be associated with the specified key.true if the value was removed.Map.remove(Object, Object)public boolean replace(byte k,
V oldValue,
V v)
replace in interface Byte2ObjectMap<V>k - key with which the specified value is associated.oldValue - value expected to be associated with the specified key.v - value to be associated with the specified key.true if the value was replaced.Map.replace(Object, Object, Object)public V replace(byte k, V v)
replace in interface Byte2ObjectMap<V>k - key with which the specified value is associated.v - value to be associated with the specified key.Map.replace(Object, Object)public V computeIfAbsent(byte k, IntFunction<? extends V> mappingFunction)
Note that contrarily to the default computeIfAbsent(),
it is not possible to not add a value for a given key, since the mappingFunction cannot
return null. If such a behavior is needed, please use the corresponding nullable version.
computeIfAbsent in interface Byte2ObjectMap<V>k - key with which the specified value is to be associated.mappingFunction - the function to compute a value.Map.computeIfAbsent(Object, java.util.function.Function)public V computeIfPresent(byte k, BiFunction<? super Byte,? super V,? extends V> remappingFunction)
computeIfPresent in interface Byte2ObjectMap<V>k - key with which the specified value is to be associated.remappingFunction - the function to compute a value.Map.computeIfPresent(Object, java.util.function.BiFunction)public V compute(byte k, BiFunction<? super Byte,? super V,? extends V> remappingFunction)
null if there is no current mapping).
If the function returns null, the mapping is removed (or remains absent if initially absent).
If the function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.
compute in interface Byte2ObjectMap<V>k - key with which the specified value is to be associated.remappingFunction - the function to compute a value.Map.compute(Object, java.util.function.BiFunction)public V merge(byte k, V v, BiFunction<? super V,? super V,? extends V> remappingFunction)
value.
Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null.merge in interface Byte2ObjectMap<V>k - key with which the resulting value is to be associated.v - the non-null value to be merged with the existing value associated with the key or, if no existing value is associated with the key, to be associated with the key.remappingFunction - the function to recompute a value if present.Map.merge(Object, Object, java.util.function.BiFunction)public void clear()
Byte2ObjectMapclear in interface Byte2ObjectMap<V>clear in interface Map<Byte,V>Map.clear()public int size()
Byte2ObjectMapInteger.MAX_VALUE elements, returns Integer.MAX_VALUE.public boolean isEmpty()
public Byte2ObjectMap.FastEntrySet<V> byte2ObjectEntrySet()
Byte2ObjectMapThis method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Map.entrySet()
so that it returns an ObjectSet
of type-specific entries (the latter makes it possible to
access keys and values with type-specific methods).
byte2ObjectEntrySet in interface Byte2ObjectMap<V>Map.entrySet()public ByteSet keySet()
AbstractByte2ObjectMapThe view is backed by the set returned by Map.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 Byte2ObjectMap<V>keySet in interface Map<Byte,V>keySet in class AbstractByte2ObjectMap<V>Map.keySet()public ObjectCollection<V> values()
AbstractByte2ObjectMapThe view is backed by the set returned by Map.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 Byte2ObjectMap<V>values in interface Map<Byte,V>values in class AbstractByte2ObjectMap<V>Map.values()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 overridden 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 Byte2ObjectOpenCustomHashMap<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.
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.Copyright © 2020. All rights reserved.