public class Reference2ByteOpenHashMap<K> extends AbstractReference2ByteMap<K> 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 FormAbstractReference2ByteMap.BasicEntry<K>, AbstractReference2ByteMap.BasicEntrySet<K>Hash.Strategy<K>Reference2ByteMap.Entry<K>, Reference2ByteMap.FastEntrySet<K>| Modifier and Type | Field and Description |
|---|---|
protected boolean |
containsNullKey
Whether this map contains the key zero.
|
protected Reference2ByteMap.FastEntrySet<K> |
entries
Cached set of entries.
|
protected float |
f
The acceptable load factor.
|
protected K[] |
key
The array of keys.
|
protected ReferenceSet<K> |
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 byte[] |
value
The array of values.
|
protected ByteCollection |
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 |
|---|
Reference2ByteOpenHashMap()
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ByteOpenHashMap(int expected)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ByteOpenHashMap(int expected,
float f)
Creates a new hash map.
|
Reference2ByteOpenHashMap(K[] k,
byte[] v)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays. |
Reference2ByteOpenHashMap(K[] k,
byte[] v,
float f)
Creates a new hash map using the elements of two parallel arrays.
|
Reference2ByteOpenHashMap(Map<? extends K,? extends Byte> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
Reference2ByteOpenHashMap(Map<? extends K,? extends Byte> m,
float f)
Creates a new hash map copying a given one.
|
Reference2ByteOpenHashMap(Reference2ByteMap<K> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
Reference2ByteOpenHashMap(Reference2ByteMap<K> m,
float f)
Creates a new hash map copying a given type-specific one.
|
| Modifier and Type | Method and Description |
|---|---|
byte |
addTo(K k,
byte incr)
Adds an increment to value currently associated with a key.
|
void |
clear()
Removes all of the mappings from this map (optional operation).
|
Reference2ByteOpenHashMap<K> |
clone()
Returns a deep copy of this map.
|
byte |
computeByte(K k,
BiFunction<? super K,? super Byte,? extends Byte> remappingFunction)
Attempts to compute a mapping for the specified key and its current mapped value (or
null if there is no current mapping). |
byte |
computeByteIfAbsent(K k,
ToIntFunction<? super K> 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.
|
byte |
computeByteIfPresent(K k,
BiFunction<? super K,? super Byte,? extends Byte> 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(Object k)
Returns true if this function contains a mapping for the specified key.
|
boolean |
containsValue(byte v)
Returns
true if this map maps one or more keys to the specified value. |
byte |
getByte(Object k)
Returns the value to which the given key is mapped.
|
byte |
getOrDefault(Object k,
byte 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() |
ReferenceSet<K> |
keySet()
Returns a type-specific-set view of the keys of this map.
|
byte |
mergeByte(K k,
byte v,
BiFunction<? super Byte,? super Byte,? extends Byte> remappingFunction)
If the specified key is not already associated with a value, associates it with the given
value. |
byte |
put(K k,
byte v)
Adds a pair to the map (optional operation).
|
void |
putAll(Map<? extends K,? extends Byte> m) |
byte |
putIfAbsent(K k,
byte 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.
|
Reference2ByteMap.FastEntrySet<K> |
reference2ByteEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
protected void |
rehash(int newN)
Rehashes the map.
|
boolean |
remove(Object k,
byte v)
Removes the entry for the specified key only if it is currently mapped to the specified value.
|
byte |
removeByte(Object k)
Removes the mapping with the given key (optional operation).
|
byte |
replace(K k,
byte v)
Replaces the entry for the specified key only if it is currently mapped to some value.
|
boolean |
replace(K k,
byte oldValue,
byte 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.
|
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.
|
equals, toStringdefaultReturnValue, defaultReturnValuefinalize, getClass, notify, notifyAll, wait, wait, waitcomputeByteIfAbsentPartial, containsValue, defaultReturnValue, defaultReturnValue, entrySet, get, getOrDefault, merge, put, putIfAbsent, remove, remove, replace, replaceapplyAsIntcompute, computeIfAbsent, computeIfPresent, forEach, replaceAllprotected transient K[] key
protected transient byte[] value
protected transient int mask
protected transient boolean containsNullKey
protected transient int n
protected transient int maxFill
f.protected final transient int minN
protected int size
protected final float f
protected transient Reference2ByteMap.FastEntrySet<K> entries
protected transient ReferenceSet<K> keys
protected transient ByteCollection values
public Reference2ByteOpenHashMap(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 map.f - the load factor.public Reference2ByteOpenHashMap(int expected)
Hash.DEFAULT_LOAD_FACTOR as load factor.expected - the expected number of elements in the hash map.public Reference2ByteOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor.public Reference2ByteOpenHashMap(Map<? extends K,? extends Byte> m, float f)
m - a Map to be copied into the new hash map.f - the load factor.public Reference2ByteOpenHashMap(Map<? extends K,? 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 Reference2ByteOpenHashMap(Reference2ByteMap<K> m, float f)
m - a type-specific map to be copied into the new hash map.f - the load factor.public Reference2ByteOpenHashMap(Reference2ByteMap<K> 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 Reference2ByteOpenHashMap(K[] 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 Reference2ByteOpenHashMap(K[] 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 void putAll(Map<? extends K,? extends Byte> m)
AbstractReference2ByteMappublic byte put(K k, byte v)
Reference2ByteFunctionput in interface Reference2ByteFunction<K>k - the key.v - the value.Function.put(Object,Object)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.protected final void shiftKeys(int pos)
pos - a starting position.public byte removeByte(Object k)
Reference2ByteFunctionremoveByte in interface Reference2ByteFunction<K>k - the key.Function.remove(Object)public byte getByte(Object k)
Reference2ByteFunctiongetByte in interface Reference2ByteFunction<K>k - the key.Function.get(Object)public boolean containsKey(Object k)
Reference2ByteMapcontainsKey in interface Reference2ByteMap<K>containsKey in interface Map<K,Byte>containsKey in class AbstractReference2ByteMap<K>k - the key.key.Map.containsKey(Object)public boolean containsValue(byte v)
Reference2ByteMaptrue if this map maps one or more keys to the specified value.containsValue in interface Reference2ByteMap<K>containsValue in class AbstractReference2ByteMap<K>Map.containsValue(Object)public byte getOrDefault(Object k, byte defaultValue)
defaultValue if this
map contains no mapping for the key.getOrDefault in interface Reference2ByteMap<K>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 byte putIfAbsent(K k, byte v)
putIfAbsent in interface Reference2ByteMap<K>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(Object k, byte v)
remove in interface Reference2ByteMap<K>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(K k, byte oldValue, byte v)
replace in interface Reference2ByteMap<K>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 byte replace(K k, byte v)
replace in interface Reference2ByteMap<K>k - key with which the specified value is associated.v - value to be associated with the specified key.Map.replace(Object, Object)public byte computeByteIfAbsent(K k, ToIntFunction<? super K> 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.
computeByteIfAbsent in interface Reference2ByteMap<K>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 byte computeByteIfPresent(K k, BiFunction<? super K,? super Byte,? extends Byte> remappingFunction)
computeByteIfPresent in interface Reference2ByteMap<K>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 byte computeByte(K k, BiFunction<? super K,? super Byte,? extends Byte> 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.
computeByte in interface Reference2ByteMap<K>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 byte mergeByte(K k, byte v, BiFunction<? super Byte,? super Byte,? extends Byte> remappingFunction)
value.
Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null.mergeByte in interface Reference2ByteMap<K>k - key with which the resulting value is to be associated.v - the 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()
Reference2ByteMapclear in interface Reference2ByteMap<K>clear in interface Map<K,Byte>Map.clear()public int size()
Reference2ByteMapInteger.MAX_VALUE elements, returns Integer.MAX_VALUE.public boolean isEmpty()
public Reference2ByteMap.FastEntrySet<K> reference2ByteEntrySet()
Reference2ByteMapThis 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).
reference2ByteEntrySet in interface Reference2ByteMap<K>Map.entrySet()public ReferenceSet<K> keySet()
AbstractReference2ByteMapThe 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 Reference2ByteMap<K>keySet in interface Map<K,Byte>keySet in class AbstractReference2ByteMap<K>Map.keySet()public ByteCollection values()
AbstractReference2ByteMapThe 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 Reference2ByteMap<K>values in interface Map<K,Byte>values in class AbstractReference2ByteMap<K>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 Reference2ByteOpenHashMap<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.Copyright © 2020. All rights reserved.