Class Object2ObjectLinkedOpenHashMap<K,V>
- java.lang.Object
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- it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction<K,V>
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- it.unimi.dsi.fastutil.objects.AbstractObject2ObjectMap<K,V>
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- it.unimi.dsi.fastutil.objects.AbstractObject2ObjectSortedMap<K,V>
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- it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenHashMap<K,V>
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- All Implemented Interfaces:
Function<K,V>
,Hash
,Object2ObjectFunction<K,V>
,Object2ObjectMap<K,V>
,Object2ObjectSortedMap<K,V>
,Serializable
,Cloneable
,Function<K,V>
,Map<K,V>
,SortedMap<K,V>
public class Object2ObjectLinkedOpenHashMap<K,V> extends AbstractObject2ObjectSortedMap<K,V> implements Serializable, Cloneable, Hash
A type-specific linked hash map with with a fast, small-footprint implementation.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.Entries returned by the type-specific
Object2ObjectMap.entrySet()
method implement the suitable type-specificPair
interface; only values are mutable.Iterators generated by this map will enumerate pairs in the same order in which they have been added to the map (addition of pairs whose key is already present in the map does not change the iteration order). Note that this order has nothing in common with the natural order of the keys. The order is kept by means of a doubly linked list, represented via an array of longs parallel to the table.
This class implements the interface of a sorted map, so to allow easy access of the iteration order: for instance, you can get the first key in iteration order with
firstKey()
without having to create an iterator; however, this class partially violates theSortedMap
contract because all submap methods throw an exception andcomparator()
returns alwaysnull
.Additional methods, such as
getAndMoveToFirst()
, make it easy to use instances of this class as a cache (e.g., with LRU policy).The iterators provided by the views of this class using are type-specific list iterators, and can be started at any element which is a key of the map, or a
NoSuchElementException
exception will be thrown. If, however, the provided element is not the first or last key in the map, the first access to the list index will require linear time, as in the worst case the entire key set must be scanned in iteration order to retrieve the positional index of the starting key. If you use just the methods of a type-specificBidirectionalIterator
, however, all operations will be performed in constant time.- See Also:
Hash
,HashCommon
, Serialized Form
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Nested Class Summary
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Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectMap
AbstractObject2ObjectMap.BasicEntry<K,V>, AbstractObject2ObjectMap.BasicEntrySet<K,V>
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Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash
Hash.Strategy<K>
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Nested classes/interfaces inherited from interface java.util.Map
Map.Entry<K extends Object,V extends Object>
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Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.objects.Object2ObjectMap
Object2ObjectMap.Entry<K,V>, Object2ObjectMap.FastEntrySet<K,V>
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Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.objects.Object2ObjectSortedMap
Object2ObjectSortedMap.FastSortedEntrySet<K,V>
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Field Summary
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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
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Constructor Summary
Constructors Constructor Description Object2ObjectLinkedOpenHashMap()
Creates a new hash map with initial expectedHash.DEFAULT_INITIAL_SIZE
entries andHash.DEFAULT_LOAD_FACTOR
as load factor.Object2ObjectLinkedOpenHashMap(int expected)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor.Object2ObjectLinkedOpenHashMap(int expected, float f)
Creates a new hash map.Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,V> m)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific one.Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,V> m, float f)
Creates a new hash map copying a given type-specific one.Object2ObjectLinkedOpenHashMap(Map<? extends K,? extends V> m)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.Object2ObjectLinkedOpenHashMap(Map<? extends K,? extends V> m, float f)
Creates a new hash map copying a given one.Object2ObjectLinkedOpenHashMap(K[] k, V[] v)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor using the elements of two parallel arrays.Object2ObjectLinkedOpenHashMap(K[] k, V[] v, float f)
Creates a new hash map using the elements of two parallel arrays.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clear()
Removes all of the mappings from this map (optional operation).Object2ObjectLinkedOpenHashMap<K,V>
clone()
Returns a deep copy of this map.Comparator<? super K>
comparator()
Returns the comparator associated with this sorted set, or null if it uses its keys' natural ordering.boolean
containsKey(Object k)
Returns true if this function contains a mapping for the specified key.boolean
containsValue(Object v)
K
firstKey()
Returns the first key of this map in iteration order.V
get(Object k)
Returns the value to which the given key is mapped.V
getAndMoveToFirst(K k)
Returns the value to which the given key is mapped; if the key is present, it is moved to the first position of the iteration order.V
getAndMoveToLast(K k)
Returns the value to which the given key is mapped; if the key is present, it is moved to the last position of the iteration order.int
hashCode()
Returns a hash code for this map.Object2ObjectSortedMap<K,V>
headMap(K to)
Returns a view of the portion of this sorted map whose keys are strictly less thantoKey
.boolean
isEmpty()
ObjectSortedSet<K>
keySet()
Returns a type-specific-set view of the keys of this map.K
lastKey()
Returns the last key of this map in iteration order.Object2ObjectSortedMap.FastSortedEntrySet<K,V>
object2ObjectEntrySet()
Returns a type-specific sorted-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)
V
putAndMoveToFirst(K k, V v)
Adds a pair to the map; if the key is already present, it is moved to the first position of the iteration order.V
putAndMoveToLast(K k, V v)
Adds a pair to the map; if the key is already present, it is moved to the last position of the iteration order.V
remove(Object k)
Removes the mapping with the given key (optional operation).V
removeFirst()
Removes the mapping associated with the first key in iteration order.V
removeLast()
Removes the mapping associated with the last key in iteration order.int
size()
Returns the number of key/value mappings in this map.Object2ObjectSortedMap<K,V>
subMap(K from, K to)
Returns a view of the portion of this sorted map whose keys range fromfromKey
, inclusive, totoKey
, exclusive.Object2ObjectSortedMap<K,V>
tailMap(K from)
Returns a view of the portion of this sorted map whose keys are greater than or equal tofromKey
.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.-
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectMap
equals, toString
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Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction
defaultReturnValue, defaultReturnValue
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Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll
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Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2ObjectFunction
andThenByte, andThenChar, andThenDouble, andThenFloat, andThenInt, andThenLong, andThenObject, andThenReference, andThenShort, composeByte, composeChar, composeDouble, composeFloat, composeInt, composeLong, composeObject, composeReference, composeShort
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Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2ObjectMap
defaultReturnValue, defaultReturnValue
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Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2ObjectSortedMap
entrySet
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Constructor Detail
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(int expected, float f)
Creates a new hash map.The actual table size will be the least power of two greater than
expected
/f
.- Parameters:
expected
- the expected number of elements in the hash map.f
- the load factor.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(int expected)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor.- Parameters:
expected
- the expected number of elements in the hash map.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap()
Creates a new hash map with initial expectedHash.DEFAULT_INITIAL_SIZE
entries andHash.DEFAULT_LOAD_FACTOR
as load factor.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(Map<? extends K,? extends V> m, float f)
Creates a new hash map copying a given one.- Parameters:
m
- aMap
to be copied into the new hash map.f
- the load factor.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(Map<? extends K,? extends V> m)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.- Parameters:
m
- aMap
to be copied into the new hash map.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,V> m, float f)
Creates a new hash map copying a given type-specific one.- Parameters:
m
- a type-specific map to be copied into the new hash map.f
- the load factor.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(Object2ObjectMap<K,V> m)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific one.- Parameters:
m
- a type-specific map to be copied into the new hash map.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(K[] k, V[] v, float f)
Creates a new hash map using the elements of two parallel arrays.- Parameters:
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.- Throws:
IllegalArgumentException
- ifk
andv
have different lengths.
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Object2ObjectLinkedOpenHashMap
public Object2ObjectLinkedOpenHashMap(K[] k, V[] v)
Creates a new hash map withHash.DEFAULT_LOAD_FACTOR
as load factor using the elements of two parallel arrays.- Parameters:
k
- the array of keys of the new hash map.v
- the array of corresponding values in the new hash map.- Throws:
IllegalArgumentException
- ifk
andv
have different lengths.
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Method Detail
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putAll
public void putAll(Map<? extends K,? extends V> m)
Description copied from class:AbstractObject2ObjectMap
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put
public V put(K k, V v)
Description copied from interface:Object2ObjectMap
Adds a pair to the map (optional operation).This default implementation just delegates to the corresponding function method.
- Specified by:
put
in interfaceFunction<K,V>
- Specified by:
put
in interfaceMap<K,V>
- Specified by:
put
in interfaceObject2ObjectFunction<K,V>
- Specified by:
put
in interfaceObject2ObjectMap<K,V>
- Parameters:
k
- the key.v
- the value.- Returns:
- the old value, or the default return value if no value was present for the given key.
- See Also:
Function.put(Object,Object)
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remove
public V remove(Object k)
Description copied from interface:Object2ObjectMap
Removes the mapping with the given key (optional operation).This default implementation just delegates to the corresponding type-specific–function method.
- Specified by:
remove
in interfaceFunction<K,V>
- Specified by:
remove
in interfaceMap<K,V>
- Specified by:
remove
in interfaceObject2ObjectFunction<K,V>
- Specified by:
remove
in interfaceObject2ObjectMap<K,V>
- Parameters:
k
- the key.- Returns:
- the old value, or the default return value if no value was present for the given key.
- See Also:
Function.remove(Object)
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removeFirst
public V removeFirst()
Removes the mapping associated with the first key in iteration order.- Returns:
- the value previously associated with the first key in iteration order.
- Throws:
NoSuchElementException
- is this map is empty.
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removeLast
public V removeLast()
Removes the mapping associated with the last key in iteration order.- Returns:
- the value previously associated with the last key in iteration order.
- Throws:
NoSuchElementException
- is this map is empty.
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getAndMoveToFirst
public V getAndMoveToFirst(K k)
Returns the value to which the given key is mapped; if the key is present, it is moved to the first position of the iteration order.- Parameters:
k
- the key.- Returns:
- the corresponding value, or the default return value if no value was present for the given key.
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getAndMoveToLast
public V getAndMoveToLast(K k)
Returns the value to which the given key is mapped; if the key is present, it is moved to the last position of the iteration order.- Parameters:
k
- the key.- Returns:
- the corresponding value, or the default return value if no value was present for the given key.
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putAndMoveToFirst
public V putAndMoveToFirst(K k, V v)
Adds a pair to the map; if the key is already present, it is moved to the first position of the iteration order.- Parameters:
k
- the key.v
- the value.- Returns:
- the old value, or the default return value if no value was present for the given key.
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putAndMoveToLast
public V putAndMoveToLast(K k, V v)
Adds a pair to the map; if the key is already present, it is moved to the last position of the iteration order.- Parameters:
k
- the key.v
- the value.- Returns:
- the old value, or the default return value if no value was present for the given key.
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get
public V get(Object k)
Description copied from interface:Object2ObjectFunction
Returns the value to which the given key is mapped.- Specified by:
get
in interfaceFunction<K,V>
- Specified by:
get
in interfaceMap<K,V>
- Specified by:
get
in interfaceObject2ObjectFunction<K,V>
- Parameters:
k
- the key.- Returns:
- the corresponding value, or the default return value if no value was present for the given key.
- See Also:
Function.get(Object)
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containsKey
public boolean containsKey(Object k)
Description copied from interface:Object2ObjectMap
Returns true if this function contains a mapping for the specified key.- Specified by:
containsKey
in interfaceFunction<K,V>
- Specified by:
containsKey
in interfaceMap<K,V>
- Specified by:
containsKey
in interfaceObject2ObjectMap<K,V>
- Overrides:
containsKey
in classAbstractObject2ObjectMap<K,V>
- Parameters:
k
- the key.- Returns:
- true if this function associates a value to
key
. - See Also:
Map.containsKey(Object)
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containsValue
public boolean containsValue(Object v)
- Specified by:
containsValue
in interfaceMap<K,V>
- Overrides:
containsValue
in classAbstractObject2ObjectMap<K,V>
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clear
public void clear()
Description copied from interface:Object2ObjectMap
Removes all of the mappings from this map (optional operation). The map will be empty after this call returns.
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size
public int size()
Description copied from interface:Object2ObjectMap
Returns the number of key/value mappings in this map. If the map contains more thanInteger.MAX_VALUE
elements, returnsInteger.MAX_VALUE
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isEmpty
public boolean isEmpty()
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firstKey
public K firstKey()
Returns the first key of this map in iteration order.
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lastKey
public K lastKey()
Returns the last key of this map in iteration order.
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tailMap
public Object2ObjectSortedMap<K,V> tailMap(K from)
Returns a view of the portion of this sorted map whose keys are greater than or equal tofromKey
.Note that this specification strengthens the one given in
SortedMap.tailMap(Object)
.This implementation just throws an
UnsupportedOperationException
.- Specified by:
tailMap
in interfaceObject2ObjectSortedMap<K,V>
- Specified by:
tailMap
in interfaceSortedMap<K,V>
- See Also:
SortedMap.tailMap(Object)
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headMap
public Object2ObjectSortedMap<K,V> headMap(K to)
Returns a view of the portion of this sorted map whose keys are strictly less thantoKey
.Note that this specification strengthens the one given in
SortedMap.headMap(Object)
.This implementation just throws an
UnsupportedOperationException
.- Specified by:
headMap
in interfaceObject2ObjectSortedMap<K,V>
- Specified by:
headMap
in interfaceSortedMap<K,V>
- See Also:
SortedMap.headMap(Object)
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subMap
public Object2ObjectSortedMap<K,V> subMap(K from, K to)
Returns a view of the portion of this sorted map whose keys range fromfromKey
, inclusive, totoKey
, exclusive.Note that this specification strengthens the one given in
SortedMap.subMap(Object,Object)
.This implementation just throws an
UnsupportedOperationException
.- Specified by:
subMap
in interfaceObject2ObjectSortedMap<K,V>
- Specified by:
subMap
in interfaceSortedMap<K,V>
- See Also:
SortedMap.subMap(Object,Object)
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comparator
public Comparator<? super K> comparator()
Returns the comparator associated with this sorted set, or null if it uses its keys' natural ordering.Note that this specification strengthens the one given in
SortedMap.comparator()
.This implementation just returns
null
.- Specified by:
comparator
in interfaceObject2ObjectSortedMap<K,V>
- Specified by:
comparator
in interfaceSortedMap<K,V>
- See Also:
SortedMap.comparator()
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object2ObjectEntrySet
public Object2ObjectSortedMap.FastSortedEntrySet<K,V> object2ObjectEntrySet()
Description copied from interface:Object2ObjectSortedMap
Returns a type-specific sorted-set view of the mappings contained in this map.Note that this specification strengthens the one given in the corresponding type-specific unsorted map.
- Specified by:
object2ObjectEntrySet
in interfaceObject2ObjectMap<K,V>
- Specified by:
object2ObjectEntrySet
in interfaceObject2ObjectSortedMap<K,V>
- Returns:
- a type-specific sorted-set view of the mappings contained in this map.
- See Also:
Object2ObjectSortedMap.entrySet()
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keySet
public ObjectSortedSet<K> keySet()
Description copied from class:AbstractObject2ObjectSortedMap
Returns a type-specific-set view of the keys of this map.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.The view is backed by the sorted 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.- Specified by:
keySet
in interfaceMap<K,V>
- Specified by:
keySet
in interfaceObject2ObjectMap<K,V>
- Specified by:
keySet
in interfaceObject2ObjectSortedMap<K,V>
- Specified by:
keySet
in interfaceSortedMap<K,V>
- Overrides:
keySet
in classAbstractObject2ObjectSortedMap<K,V>
- Returns:
- a sorted set view of the keys of this map; it may be safely cast to a type-specific interface.
- See Also:
Map.keySet()
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values
public ObjectCollection<V> values()
Description copied from class:AbstractObject2ObjectSortedMap
Returns a type-specific-set view of the values of this map.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.The view is backed by the sorted 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.- Specified by:
values
in interfaceMap<K,V>
- Specified by:
values
in interfaceObject2ObjectMap<K,V>
- Specified by:
values
in interfaceObject2ObjectSortedMap<K,V>
- Specified by:
values
in interfaceSortedMap<K,V>
- Overrides:
values
in classAbstractObject2ObjectSortedMap<K,V>
- Returns:
- a type-specific collection view of the values contained in this map.
- See Also:
Map.values()
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trim
public boolean trim()
Rehashes the map, making the table as small as possible.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.
- Returns:
- true if there was enough memory to trim the map.
- See Also:
trim(int)
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trim
public boolean trim(int n)
Rehashes this map if the table is too large.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.
- Parameters:
n
- the threshold for the trimming.- Returns:
- true if there was enough memory to trim the map.
- See Also:
trim()
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clone
public Object2ObjectLinkedOpenHashMap<K,V> clone()
Returns a deep copy of this map.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.
- Returns:
- a deep copy of this map.
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hashCode
public int hashCode()
Returns a hash code for this map. This method overrides the generic method provided by the superclass. Sinceequals()
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.
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