Class ObjectLinkedOpenCustomHashSet<K>
- All Implemented Interfaces:
Hash
,ObjectBidirectionalIterable<K>
,ObjectCollection<K>
,ObjectIterable<K>
,ObjectSet<K>
,ObjectSortedSet<K>
,Serializable
,Cloneable
,Iterable<K>
,Collection<K>
,SequencedCollection<K>
,SequencedSet<K>
,Set<K>
,SortedSet<K>
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, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create sets 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.
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.
- See Also:
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Nested Class Summary
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash
Hash.Strategy<K>
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Field Summary
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
ConstructorDescriptionObjectLinkedOpenCustomHashSet
(int expected, float f, Hash.Strategy<? super K> strategy) Creates a new hash set.ObjectLinkedOpenCustomHashSet
(int expected, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor.ObjectLinkedOpenCustomHashSet
(Hash.Strategy<? super K> strategy) Creates a new hash set with initial expectedHash.DEFAULT_INITIAL_SIZE
elements andHash.DEFAULT_LOAD_FACTOR
as load factor.ObjectLinkedOpenCustomHashSet
(ObjectCollection<? extends K> c, float f, Hash.Strategy<? super K> strategy) Creates a new hash set copying a given type-specific collection.ObjectLinkedOpenCustomHashSet
(ObjectCollection<? extends K> c, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific collection.ObjectLinkedOpenCustomHashSet
(Collection<? extends K> c, float f, Hash.Strategy<? super K> strategy) Creates a new hash set copying a given collection.ObjectLinkedOpenCustomHashSet
(Collection<? extends K> c, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given collection.ObjectLinkedOpenCustomHashSet
(Iterator<? extends K> i, float f, Hash.Strategy<? super K> strategy) Creates a new hash set using elements provided by a type-specific iterator.ObjectLinkedOpenCustomHashSet
(Iterator<? extends K> i, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by a type-specific iterator.ObjectLinkedOpenCustomHashSet
(K[] a, float f, Hash.Strategy<? super K> strategy) Creates a new hash set copying the elements of an array.ObjectLinkedOpenCustomHashSet
(K[] a, int offset, int length, float f, Hash.Strategy<? super K> strategy) Creates a new hash set and fills it with the elements of a given array.ObjectLinkedOpenCustomHashSet
(K[] a, int offset, int length, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor and fills it with the elements of a given array.ObjectLinkedOpenCustomHashSet
(K[] a, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying the elements of an array. -
Method Summary
Modifier and TypeMethodDescriptionboolean
boolean
addAll
(Collection<? extends K> c) boolean
Adds a key to the set; if the key is already present, it is moved to the first position of the iteration order.boolean
Adds a key to the set; if the key is already present, it is moved to the last position of the iteration order.Add a random element if not present, get the existing value if already present.void
clear()
clone()
Returns a deep copy of this set.Comparator
<? super K> boolean
void
ensureCapacity
(int capacity) Ensures that this set can hold a certain number of elements without rehashing.first()
Returns the first element of this set in iteration order.void
Returns the element of this set that is equal to the given key, ornull
.int
hashCode()
Returns a hash code for this set.Returns a view of the portion of this sorted set whose elements are strictly less thantoElement
.boolean
isEmpty()
iterator()
Returns a type-specific list iterator on the elements in this set, starting from the first element.Returns a type-specific list iterator on the elements in this set, starting from a given element of the set.last()
Returns the last element of this set in iteration order.boolean
Removes the first key in iteration order.Removes the the last key in iteration order.int
size()
Returns a type-specific spliterator on the elements of this sorted-set.Hash.Strategy
<? super K> strategy()
Returns the hashing strategy.Returns a view of the portion of this sorted set whose elements range fromfromElement
, inclusive, totoElement
, exclusive.Returns a view of the portion of this sorted set whose elements are greater than or equal tofromElement
.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.Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectSet
equals
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectCollection
toString
Methods inherited from class java.util.AbstractCollection
containsAll, removeAll, retainAll, toArray, toArray
Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream, toArray
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Constructor Details
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ObjectLinkedOpenCustomHashSet
Creates a new hash set.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 set.f
- the load factor.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor.- Parameters:
expected
- the expected number of elements in the hash set.strategy
- the strategy.
-
ObjectLinkedOpenCustomHashSet
Creates a new hash set with initial expectedHash.DEFAULT_INITIAL_SIZE
elements andHash.DEFAULT_LOAD_FACTOR
as load factor.- Parameters:
strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
public ObjectLinkedOpenCustomHashSet(Collection<? extends K> c, float f, Hash.Strategy<? super K> strategy) Creates a new hash set copying a given collection.- Parameters:
c
- aCollection
to be copied into the new hash set.f
- the load factor.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given collection.- Parameters:
c
- aCollection
to be copied into the new hash set.strategy
- the strategy.
-
ObjectLinkedOpenCustomHashSet
public ObjectLinkedOpenCustomHashSet(ObjectCollection<? extends K> c, float f, Hash.Strategy<? super K> strategy) Creates a new hash set copying a given type-specific collection.- Parameters:
c
- a type-specific collection to be copied into the new hash set.f
- the load factor.strategy
- the strategy.
-
ObjectLinkedOpenCustomHashSet
public ObjectLinkedOpenCustomHashSet(ObjectCollection<? extends K> c, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific collection.- Parameters:
c
- a type-specific collection to be copied into the new hash set.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
public ObjectLinkedOpenCustomHashSet(Iterator<? extends K> i, float f, Hash.Strategy<? super K> strategy) Creates a new hash set using elements provided by a type-specific iterator.- Parameters:
i
- a type-specific iterator whose elements will fill the set.f
- the load factor.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor using elements provided by a type-specific iterator.- Parameters:
i
- a type-specific iterator whose elements will fill the set.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
public ObjectLinkedOpenCustomHashSet(K[] a, int offset, int length, float f, Hash.Strategy<? super K> strategy) Creates a new hash set and fills it with the elements of a given array.- Parameters:
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.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
public ObjectLinkedOpenCustomHashSet(K[] a, int offset, int length, Hash.Strategy<? super K> strategy) Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor and fills it with the elements of a given array.- Parameters:
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.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
Creates a new hash set copying the elements of an array.- Parameters:
a
- an array to be copied into the new hash set.f
- the load factor.strategy
- the strategy.
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ObjectLinkedOpenCustomHashSet
Creates a new hash set withHash.DEFAULT_LOAD_FACTOR
as load factor copying the elements of an array.- Parameters:
a
- an array to be copied into the new hash set.strategy
- the strategy.
-
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Method Details
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strategy
Returns the hashing strategy.- Returns:
- the hashing strategy of this custom hash set.
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ensureCapacity
public void ensureCapacity(int capacity) Ensures that this set can hold a certain number of elements without rehashing.- Parameters:
capacity
- a number of elements; there will be no rehashing unless the set size exceeds this number.
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addAll
- Specified by:
addAll
in interfaceCollection<K>
- Specified by:
addAll
in interfaceSet<K>
- Overrides:
addAll
in classAbstractCollection<K>
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add
- Specified by:
add
in interfaceCollection<K>
- Specified by:
add
in interfaceSet<K>
- Overrides:
add
in classAbstractCollection<K>
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addOrGet
Add a random element if not present, get the existing value if already present. This is equivalent to (but faster than) doing a:K exist = set.get(k); if (exist == null) { set.add(k); exist = k; }
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remove
- Specified by:
remove
in interfaceCollection<K>
- Specified by:
remove
in interfaceSet<K>
- Overrides:
remove
in classAbstractCollection<K>
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contains
- Specified by:
contains
in interfaceCollection<K>
- Specified by:
contains
in interfaceSet<K>
- Overrides:
contains
in classAbstractCollection<K>
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get
Returns the element of this set that is equal to the given key, ornull
.- Returns:
- the element of this set that is equal to the given key, or
null
.
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removeFirst
Removes the first key in iteration order.- Specified by:
removeFirst
in interfaceSequencedCollection<K>
- Specified by:
removeFirst
in interfaceSortedSet<K>
- Returns:
- the first key.
- Throws:
NoSuchElementException
- is this set is empty.
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removeLast
Removes the the last key in iteration order.- Specified by:
removeLast
in interfaceSequencedCollection<K>
- Specified by:
removeLast
in interfaceSortedSet<K>
- Returns:
- the last key.
- Throws:
NoSuchElementException
- is this set is empty.
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addAndMoveToFirst
Adds a key to the set; if the key is already present, it is moved to the first position of the iteration order.- Parameters:
k
- the key.- Returns:
- true if the key was not present.
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addAndMoveToLast
Adds a key to the set; if the key is already present, it is moved to the last position of the iteration order.- Parameters:
k
- the key.- Returns:
- true if the key was not present.
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clear
public void clear()- Specified by:
clear
in interfaceCollection<K>
- Specified by:
clear
in interfaceSet<K>
- Overrides:
clear
in classAbstractCollection<K>
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size
public int size()- Specified by:
size
in interfaceCollection<K>
- Specified by:
size
in interfaceSet<K>
- Specified by:
size
in classAbstractCollection<K>
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isEmpty
public boolean isEmpty()- Specified by:
isEmpty
in interfaceCollection<K>
- Specified by:
isEmpty
in interfaceSet<K>
- Overrides:
isEmpty
in classAbstractCollection<K>
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first
Returns the first element of this set in iteration order. -
last
Returns the last element of this set in iteration order. -
tailSet
Returns a view of the portion of this sorted set whose elements are greater than or equal tofromElement
.- Specified by:
tailSet
in interfaceObjectSortedSet<K>
- Specified by:
tailSet
in interfaceSortedSet<K>
- See Also:
- Implementation Specification:
- This implementation just throws an
UnsupportedOperationException
.
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headSet
Returns a view of the portion of this sorted set whose elements are strictly less thantoElement
.- Specified by:
headSet
in interfaceObjectSortedSet<K>
- Specified by:
headSet
in interfaceSortedSet<K>
- See Also:
- Implementation Specification:
- This implementation just throws an
UnsupportedOperationException
.
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subSet
Returns a view of the portion of this sorted set whose elements range fromfromElement
, inclusive, totoElement
, exclusive.- Specified by:
subSet
in interfaceObjectSortedSet<K>
- Specified by:
subSet
in interfaceSortedSet<K>
- See Also:
- Implementation Specification:
- This implementation just throws an
UnsupportedOperationException
.
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comparator
- Specified by:
comparator
in interfaceSortedSet<K>
- Implementation Specification:
- This implementation just returns
null
.
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iterator
Returns a type-specific list iterator on the elements in this set, starting from a given element of the set. Please see the class documentation for implementation details.- Specified by:
iterator
in interfaceObjectSortedSet<K>
- Parameters:
from
- an element to start from.- Returns:
- a type-specific list iterator starting at the given element.
- Throws:
IllegalArgumentException
- iffrom
does not belong to the set.
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iterator
Returns a type-specific list iterator on the elements in this set, starting from the first element. Please see the class documentation for implementation details.- Specified by:
iterator
in interfaceCollection<K>
- Specified by:
iterator
in interfaceIterable<K>
- Specified by:
iterator
in interfaceObjectBidirectionalIterable<K>
- Specified by:
iterator
in interfaceObjectCollection<K>
- Specified by:
iterator
in interfaceObjectIterable<K>
- Specified by:
iterator
in interfaceObjectSet<K>
- Specified by:
iterator
in interfaceObjectSortedSet<K>
- Specified by:
iterator
in interfaceSet<K>
- Specified by:
iterator
in classAbstractObjectSortedSet<K>
- Returns:
- a type-specific list iterator starting at the first element.
- See Also:
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spliterator
Returns a type-specific spliterator on the elements of this sorted-set.SortedSet spliterators must report at least
Spliterator.DISTINCT
,Spliterator.ORDERED
, andSpliterator.SORTED
. The returned spliterator'sgetComparator()
must be the same (or at the very least, consistent with) this instance'sSortedSet.comparator()
.See
SortedSet.spliterator()
for more documentation on the requirements of the returned spliterator.There isn't a way to split efficiently while still preserving order for a linked data structure, so this implementation is just backed by the iterator. Thus, this spliterator is not well optimized for parallel streams.
Note, contrary to the specification of
SortedSet
, this spliterator does not, reportSpliterator.SORTED
. This is because iteration order is based on insertion order, not natural ordering.- Specified by:
spliterator
in interfaceCollection<K>
- Specified by:
spliterator
in interfaceIterable<K>
- Specified by:
spliterator
in interfaceObjectCollection<K>
- Specified by:
spliterator
in interfaceObjectIterable<K>
- Specified by:
spliterator
in interfaceObjectSet<K>
- Specified by:
spliterator
in interfaceObjectSortedSet<K>
- Specified by:
spliterator
in interfaceSet<K>
- Specified by:
spliterator
in interfaceSortedSet<K>
- Returns:
- a type-specific spliterator on the elements of this collection.
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forEach
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trim
public boolean trim()Rehashes this set, 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 set.
- See Also:
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trim
public boolean trim(int n) Rehashes this set 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 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.
- Parameters:
n
- the threshold for the trimming.- Returns:
- true if there was enough memory to trim the set.
- See Also:
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clone
Returns a deep copy of this set.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.
- Returns:
- a deep copy of this set.
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hashCode
public int hashCode()Returns a hash code for this set. 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.- Specified by:
hashCode
in interfaceCollection<K>
- Specified by:
hashCode
in interfaceSet<K>
- Overrides:
hashCode
in classAbstractObjectSet<K>
- Returns:
- a hash code for this set.
-