public class Object2ReferenceOpenCustomHashMap<K,V> extends AbstractObject2ReferenceMap<K,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 FormAbstractObject2ReferenceMap.BasicEntry<K,V>Hash.Strategy<K>Object2ReferenceMap.Entry<K,V>, Object2ReferenceMap.FastEntrySet<K,V>DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR| Constructor and Description |
|---|
Object2ReferenceOpenCustomHashMap(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. |
Object2ReferenceOpenCustomHashMap(int expected,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map.
|
Object2ReferenceOpenCustomHashMap(int expected,
Hash.Strategy<K> strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load
factor. |
Object2ReferenceOpenCustomHashMap(K[] k,
V[] v,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map using the elements of two parallel arrays.
|
Object2ReferenceOpenCustomHashMap(K[] k,
V[] 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. |
Object2ReferenceOpenCustomHashMap(Map<? extends K,? extends V> m,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map copying a given one.
|
Object2ReferenceOpenCustomHashMap(Map<? extends K,? extends V> m,
Hash.Strategy<K> strategy)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load
factor copying a given one. |
Object2ReferenceOpenCustomHashMap(Object2ReferenceMap<K,V> m,
float f,
Hash.Strategy<K> strategy)
Creates a new hash map copying a given type-specific one.
|
Object2ReferenceOpenCustomHashMap(Object2ReferenceMap<K,V> 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 |
|---|---|
void |
clear()
Removes all of the mappings from this map (optional operation).
|
Object2ReferenceOpenCustomHashMap<K,V> |
clone()
Returns a deep copy of this map.
|
boolean |
containsKey(Object k)
Returns true if this function contains a mapping for the specified key.
|
boolean |
containsValue(Object v)
Returns true if this map maps one or more keys to the
specified value.
|
V |
get(Object k)
Returns the value to which the specified key is mapped,
or
null if this map contains no mapping for the key. |
int |
hashCode()
Returns a hash code for this map.
|
boolean |
isEmpty()
Returns true if this map contains no key-value mappings.
|
ObjectSet<K> |
keySet()
Returns a type-specific-set view of the keys of this map.
|
Object2ReferenceMap.FastEntrySet<K,V> |
object2ReferenceEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
V |
put(K k,
V v)
Adds a pair to the map (optional operation).
|
void |
putAll(Map<? extends K,? extends V> m)
Copies all of the mappings from the specified map to this map
(optional operation).
|
V |
remove(Object k)
Removes the mapping with the given key (optional operation).
|
int |
size()
Returns the number of key/value mappings in this map.
|
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.
|
ReferenceCollection<V> |
values()
Returns a type-specific-set view of the values of this map.
|
equals, toStringdefaultReturnValue, defaultReturnValuedefaultReturnValue, defaultReturnValue, entrySetcompute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAllpublic Object2ReferenceOpenCustomHashMap(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 map.f - the load factor.strategy - the strategy.public Object2ReferenceOpenCustomHashMap(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 Object2ReferenceOpenCustomHashMap(Hash.Strategy<K> strategy)
Hash.DEFAULT_INITIAL_SIZE entries and
Hash.DEFAULT_LOAD_FACTOR as load factor.strategy - the strategy.public Object2ReferenceOpenCustomHashMap(Map<? extends K,? extends V> 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 Object2ReferenceOpenCustomHashMap(Map<? extends K,? extends V> 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 Object2ReferenceOpenCustomHashMap(Object2ReferenceMap<K,V> 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 Object2ReferenceOpenCustomHashMap(Object2ReferenceMap<K,V> 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 Object2ReferenceOpenCustomHashMap(K[] k, V[] 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 Object2ReferenceOpenCustomHashMap(K[] k, V[] 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 void putAll(Map<? extends K,? extends V> m)
AbstractObject2ReferenceMapput(k, v) on this map once
for each mapping from key k to value v in the
specified map. The behavior of this operation is undefined if the
specified map is modified while the operation is in progress.public V put(K k, V v)
Object2ReferenceMapThis default implementation just delegates to the corresponding function method.
put in interface Object2ReferenceFunction<K,V>put in interface Object2ReferenceMap<K,V>put in interface Map<K,V>k - the key.v - the value.Function.put(Object,Object)public V remove(Object k)
Object2ReferenceMapThis default implementation just delegates to the corresponding type-specific–function method.
remove in interface Object2ReferenceFunction<K,V>remove in interface Object2ReferenceMap<K,V>remove in interface Map<K,V>k - the key.Function.remove(Object)public V get(Object k)
java.util.Mapnull if this map contains no mapping for the key.
More formally, if this map contains a mapping from a key
k to a value v such that (key==null ? k==null :
key.equals(k)), then this method returns v; otherwise
it returns null. (There can be at most one such mapping.)
If this map permits null values, then a return value of
null does not necessarily indicate that the map
contains no mapping for the key; it's also possible that the map
explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.
get in interface Object2ReferenceFunction<K,V>get in interface Map<K,V>k - the key whose associated value is to be returnednull if this map contains no mapping for the keyFunction.get(Object)public boolean containsKey(Object k)
Object2ReferenceMapcontainsKey in interface Object2ReferenceMap<K,V>containsKey in interface Map<K,V>containsKey in class AbstractObject2ReferenceMap<K,V>k - the key.key.Map.containsKey(Object)public boolean containsValue(Object v)
java.util.MapcontainsValue in interface Map<K,V>containsValue in class AbstractObject2ReferenceMap<K,V>v - value whose presence in this map is to be testedpublic void clear()
Object2ReferenceMapclear in interface Object2ReferenceMap<K,V>clear in interface Map<K,V>Map.clear()public int size()
Object2ReferenceMapInteger.MAX_VALUE elements, returns
Integer.MAX_VALUE.public boolean isEmpty()
java.util.Mappublic Object2ReferenceMap.FastEntrySet<K,V> object2ReferenceEntrySet()
Object2ReferenceMap
This 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).
object2ReferenceEntrySet in interface Object2ReferenceMap<K,V>Map.entrySet()public ObjectSet<K> keySet()
AbstractObject2ReferenceMap
The 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 Object2ReferenceMap<K,V>keySet in interface Map<K,V>keySet in class AbstractObject2ReferenceMap<K,V>Map.keySet()public ReferenceCollection<V> values()
AbstractObject2ReferenceMap
The 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 Object2ReferenceMap<K,V>values in interface Map<K,V>values in class AbstractObject2ReferenceMap<K,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()public Object2ReferenceOpenCustomHashMap<K,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.hashCode in interface Map<K,V>hashCode in class AbstractObject2ReferenceMap<K,V>Object.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)