public class ReferenceLinkedOpenHashSet<K> extends AbstractReferenceSortedSet<K> implements Serializable, Cloneable, Hash
Instances of this class use a hash table to represent a set. 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, 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.
Iterators generated by this set will enumerate elements in the same order in which they have been added to the set (addition of elements already present in the set 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 set, so to allow easy access of the iteration order: for instance, you can get the first element in iteration order with first()
without
having to create an iterator; however, this class partially violates the SortedSet
contract because all subset methods throw an exception and comparator()
returns always
null
.
Additional methods, such as addAndMoveToFirst()
, make it easy to use instances of this class as a cache (e.g., with LRU policy).
The iterators provided by this class are type-specific list iterators, and can be started at any element which is in the set (if the provided element
is not in the set, a NoSuchElementException
exception will be thrown). If, however, the provided element is not the first or last element in the set, the first access to the list index will
require linear time, as in the worst case the entire set must be scanned in iteration order to retrieve the positional index of the starting element. If you use just the methods of a type-specific
BidirectionalIterator
, however, all operations will be performed in constant time.
Hash
,
HashCommon
,
Serialized FormHash.Strategy<K>
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
Constructor and Description |
---|
ReferenceLinkedOpenHashSet()
Creates a new hash set with initial expected
Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor. |
ReferenceLinkedOpenHashSet(Collection<? extends K> c)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection. |
ReferenceLinkedOpenHashSet(Collection<? extends K> c,
float f)
Creates a new hash set copying a given collection.
|
ReferenceLinkedOpenHashSet(int expected)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
ReferenceLinkedOpenHashSet(int expected,
float f)
Creates a new hash set.
|
ReferenceLinkedOpenHashSet(Iterator<? extends K> i)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator. |
ReferenceLinkedOpenHashSet(Iterator<? extends K> i,
float f)
Creates a new hash set using elements provided by a type-specific iterator.
|
ReferenceLinkedOpenHashSet(K[] a)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array. |
ReferenceLinkedOpenHashSet(K[] a,
float f)
Creates a new hash set copying the elements of an array.
|
ReferenceLinkedOpenHashSet(K[] a,
int offset,
int length)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor and fills it with the elements of a given array. |
ReferenceLinkedOpenHashSet(K[] a,
int offset,
int length,
float f)
Creates a new hash set and fills it with the elements of a given array.
|
ReferenceLinkedOpenHashSet(ReferenceCollection<? extends K> c)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection. |
ReferenceLinkedOpenHashSet(ReferenceCollection<? extends K> c,
float f)
Creates a new hash set copying a given type-specific collection.
|
Modifier and Type | Method and Description |
---|---|
boolean |
add(K k) |
boolean |
addAll(Collection<? extends K> c)
Adds all elements of the given collection to this collection.
|
boolean |
addAndMoveToFirst(K k)
Adds a key to the set; if the key is already present, it is moved to the first position of the iteration order.
|
boolean |
addAndMoveToLast(K k)
Adds a key to the set; if the key is already present, it is moved to the last position of the iteration order.
|
void |
clear() |
ReferenceLinkedOpenHashSet<K> |
clone()
Returns a deep copy of this set.
|
Comparator<? super K> |
comparator() |
boolean |
contains(Object k) |
K |
first()
Returns the first element of this set in iteration order.
|
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 set.
|
ReferenceSortedSet<K> |
headSet(K to)
Returns a view of the portion of this sorted set whose elements are strictly less than
toElement . |
boolean |
isEmpty() |
ObjectListIterator<K> |
iterator()
Returns a type-specific iterator on the elements of this collection.
|
ObjectListIterator<K> |
iterator(K from)
Returns a type-specific list iterator on the elements in this set, starting from a given element of the set.
|
K |
last()
Returns the last element of this set in iteration order.
|
boolean |
rehash()
Deprecated.
A no-op.
|
boolean |
remove(Object k)
Removes an element from this set.
|
K |
removeFirst()
Removes the first key in iteration order.
|
K |
removeLast()
Removes the the last key in iteration order.
|
int |
size() |
ReferenceSortedSet<K> |
subSet(K from,
K to)
Returns a view of the portion of this sorted set whose elements range from
fromElement , inclusive, to toElement , exclusive. |
ReferenceSortedSet<K> |
tailSet(K from)
Returns a view of the portion of this sorted set whose elements are greater than or equal to
fromElement . |
boolean |
trim()
Rehashes this set, making the table as small as possible.
|
boolean |
trim(int n)
Rehashes this set if the table is too large.
|
objectIterator
equals
containsAll, removeAll, retainAll, toArray, toArray, toString
toArray
spliterator
containsAll, equals, removeAll, retainAll, toArray, toArray
parallelStream, removeIf, stream
public ReferenceLinkedOpenHashSet(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 ReferenceLinkedOpenHashSet(int expected)
Hash.DEFAULT_LOAD_FACTOR
as load factor.expected
- the expected number of elements in the hash set.public ReferenceLinkedOpenHashSet()
Hash.DEFAULT_INITIAL_SIZE
elements and Hash.DEFAULT_LOAD_FACTOR
as load factor.public ReferenceLinkedOpenHashSet(Collection<? extends K> c, float f)
c
- a Collection
to be copied into the new hash set.f
- the load factor.public ReferenceLinkedOpenHashSet(Collection<? extends K> c)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given collection.c
- a Collection
to be copied into the new hash set.public ReferenceLinkedOpenHashSet(ReferenceCollection<? extends K> c, float f)
c
- a type-specific collection to be copied into the new hash set.f
- the load factor.public ReferenceLinkedOpenHashSet(ReferenceCollection<? extends K> c)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific collection.c
- a type-specific collection to be copied into the new hash set.public ReferenceLinkedOpenHashSet(Iterator<? extends K> i, float f)
i
- a type-specific iterator whose elements will fill the set.f
- the load factor.public ReferenceLinkedOpenHashSet(Iterator<? extends K> i)
Hash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by a type-specific iterator.i
- a type-specific iterator whose elements will fill the set.public ReferenceLinkedOpenHashSet(K[] a, int offset, int length, float f)
a
- an array whose elements will be used to fill the set.offset
- the first element to use.length
- the number of elements to use.f
- the load factor.public ReferenceLinkedOpenHashSet(K[] a, int offset, int length)
Hash.DEFAULT_LOAD_FACTOR
as load factor and fills it with the elements of a given array.a
- an array whose elements will be used to fill the set.offset
- the first element to use.length
- the number of elements to use.public ReferenceLinkedOpenHashSet(K[] a, float f)
a
- an array to be copied into the new hash set.f
- the load factor.public ReferenceLinkedOpenHashSet(K[] a)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying the elements of an array.a
- an array to be copied into the new hash set.public boolean addAll(Collection<? extends K> c)
addAll
in interface Collection<K>
addAll
in interface Set<K>
addAll
in class AbstractReferenceCollection<K>
c
- a collection.true
if this collection changed as a result of the call.public boolean add(K k)
add
in interface Collection<K>
add
in interface Set<K>
add
in class AbstractReferenceCollection<K>
public boolean remove(Object k)
ReferenceSet
Note that the corresponding method of the type-specific collection is rem()
. This unfortunate situation is caused by the clash with the similarly named index-based method in the
List
interface.
remove
in interface ReferenceSet<K>
remove
in interface Collection<K>
remove
in interface Set<K>
remove
in class AbstractReferenceSet<K>
Collection.remove(Object)
public boolean contains(Object k)
contains
in interface Collection<K>
contains
in interface Set<K>
contains
in class AbstractCollection<K>
public K removeFirst()
NoSuchElementException
- is this set is empty.public K removeLast()
NoSuchElementException
- is this set is empty.public boolean addAndMoveToFirst(K k)
k
- the key.public boolean addAndMoveToLast(K k)
k
- the key.public void clear()
clear
in interface Collection<K>
clear
in interface Set<K>
clear
in class AbstractCollection<K>
public int size()
size
in interface Collection<K>
size
in interface Set<K>
size
in class AbstractCollection<K>
public boolean isEmpty()
isEmpty
in interface Collection<K>
isEmpty
in interface Set<K>
isEmpty
in class AbstractReferenceCollection<K>
@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 K first()
public K last()
public ReferenceSortedSet<K> tailSet(K from)
ReferenceSortedSet
fromElement
.
Note that this specification strengthens the one given in SortedSet.tailSet(Object)
.
tailSet
in interface ReferenceSortedSet<K>
tailSet
in interface SortedSet<K>
SortedSet.tailSet(Object)
public ReferenceSortedSet<K> headSet(K to)
ReferenceSortedSet
toElement
.
Note that this specification strengthens the one given in SortedSet.headSet(Object)
.
headSet
in interface ReferenceSortedSet<K>
headSet
in interface SortedSet<K>
SortedSet.headSet(Object)
public ReferenceSortedSet<K> subSet(K from, K to)
ReferenceSortedSet
fromElement
, inclusive, to toElement
, exclusive.
Note that this specification strengthens the one given in SortedSet.subSet(Object,Object)
.
subSet
in interface ReferenceSortedSet<K>
subSet
in interface SortedSet<K>
SortedSet.subSet(Object,Object)
public Comparator<? super K> comparator()
comparator
in interface SortedSet<K>
public ObjectListIterator<K> iterator(K from)
iterator
in interface ReferenceSortedSet<K>
from
- an element to start from.IllegalArgumentException
- if from
does not belong to the set.public ObjectListIterator<K> iterator()
ReferenceCollection
Note that this specification strengthens the one given in Iterable.iterator()
, which was already strengthened in the corresponding type-specific class, but was weakened by
the fact that this interface extends Collection
.
iterator
in interface ObjectIterable<K>
iterator
in interface ReferenceCollection<K>
iterator
in interface ReferenceSet<K>
iterator
in interface ReferenceSortedSet<K>
iterator
in interface Iterable<K>
iterator
in interface Collection<K>
iterator
in interface Set<K>
iterator
in class AbstractReferenceSortedSet<K>
@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 set in a table of size N.
size()
)
This method is useful when reusing sets. Clearing a set leaves the table size untouched. If you are reusing a set 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 sets.
n
- the threshold for the trimming.trim()
public ReferenceLinkedOpenHashSet<K> clone()
This method performs a deep copy of this hash set; the data stored in the set, 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 Collection<K>
hashCode
in interface Set<K>
hashCode
in class AbstractReferenceSet<K>