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java.lang.Objectit.unimi.dsi.fastutil.objects.AbstractObjectCollection<K>
it.unimi.dsi.fastutil.objects.AbstractObjectSet<K>
it.unimi.dsi.fastutil.objects.AbstractObjectSortedSet<K>
it.unimi.dsi.fastutil.objects.ObjectLinkedOpenHashSet<K>
public class ObjectLinkedOpenHashSet<K>
A type-specific linked hash set with with a fast, small-footprint implementation.
Instances of this class use a hash table to represent a set. The table is
enlarged as needed when new entries are created, but it is never made
smaller (even on a clear()
). A family of trimming
methods lets you control the size of the table; this is particularly useful
if you reuse instances of this class.
The enlargement speed is controlled by the growth factor, a
positive number. If the growth factor is p, then the table is
enlarged each time roughly by a factor 2p/16. By default, p is
Hash.DEFAULT_GROWTH_FACTOR
, which means that the table is doubled at
each enlargement, but one can easily set more or less aggressive policies by
calling growthFactor(int)
(note that the growth factor is not serialized:
deserialized tables gets the default growth factor).
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
.
The iterators provided by this class are type-specific list iterators. However, creation of an iterator
using a starting point is going to be very expensive, as the chosen starting
point must be linearly searched for, unless it is last()
, in which
case the iterator is created in constant time.
Note that deletions in a linked table require scanning the list until the element to be removed is found. The only exceptions are the first element, the last element, and deletions performed using an iterator.
Hash
,
HashCommon
,
Serialized FormNested Class Summary |
---|
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash |
---|
Hash.Strategy<K> |
Field Summary | |
---|---|
static long |
serialVersionUID
|
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 |
Constructor Summary | |
---|---|
ObjectLinkedOpenHashSet()
Creates a new hash set with Hash.DEFAULT_INITIAL_SIZE elements
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
ObjectLinkedOpenHashSet(Collection<? extends K> c)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor
copying a given collection. |
|
ObjectLinkedOpenHashSet(Collection<? extends K> c,
float f)
Creates a new hash set copying a given collection. |
|
ObjectLinkedOpenHashSet(int n)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
ObjectLinkedOpenHashSet(int n,
float f)
Creates a new hash set. |
|
ObjectLinkedOpenHashSet(K[] a)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor
copying the elements of an array. |
|
ObjectLinkedOpenHashSet(K[] a,
float f)
Creates a new hash set copying the elements of an array. |
|
ObjectLinkedOpenHashSet(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. |
|
ObjectLinkedOpenHashSet(K[] a,
int offset,
int length,
float f)
Creates a new hash set and fills it with the elements of a given array. |
|
ObjectLinkedOpenHashSet(ObjectCollection<? extends K> c)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor
copying a given type-specific collection. |
|
ObjectLinkedOpenHashSet(ObjectCollection<? extends K> c,
float f)
Creates a new hash set copying a given type-specific collection. |
|
ObjectLinkedOpenHashSet(ObjectIterator<K> i)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator. |
|
ObjectLinkedOpenHashSet(ObjectIterator<K> i,
float f)
Creates a new hash set using elements provided by a type-specific iterator. |
Method Summary | |
---|---|
boolean |
add(K k)
|
void |
clear()
|
Object |
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()
Gets the growth factor. |
void |
growthFactor(int growthFactor)
Sets the growth factor. |
int |
hashCode()
Returns a hash code for this set. |
ObjectSortedSet<K> |
headSet(K to)
Returns a view of the portion of this sorted set whose elements are strictly less than toElement . |
boolean |
isEmpty()
|
ObjectBidirectionalIterator<K> |
iterator()
Returns a type-specific iterator on the elements of this collection. |
ObjectBidirectionalIterator<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()
Rehashes this set without changing the table size. |
boolean |
remove(Object k)
Removes an element from this set. |
int |
size()
|
ObjectSortedSet<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. |
ObjectSortedSet<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. |
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectSortedSet |
---|
objectIterator |
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectSet |
---|
equals |
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObjectCollection |
---|
addAll, containsAll, removeAll, retainAll, toArray, toArray, toString |
Methods inherited from class java.lang.Object |
---|
getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface it.unimi.dsi.fastutil.objects.ObjectCollection |
---|
toArray |
Methods inherited from interface java.util.Set |
---|
addAll, containsAll, equals, removeAll, retainAll, toArray, toArray |
Methods inherited from interface java.util.Set |
---|
addAll, containsAll, equals, removeAll, retainAll, toArray, toArray |
Field Detail |
---|
public static final long serialVersionUID
Constructor Detail |
---|
public ObjectLinkedOpenHashSet(int n, float f)
n
/f
.
n
- the expected number of elements in the hash set.f
- the load factor.Hash.PRIMES
public ObjectLinkedOpenHashSet(int n)
Hash.DEFAULT_LOAD_FACTOR
as load factor.
n
- the expected number of elements in the hash set.public ObjectLinkedOpenHashSet()
Hash.DEFAULT_INITIAL_SIZE
elements
and Hash.DEFAULT_LOAD_FACTOR
as load factor.
public ObjectLinkedOpenHashSet(Collection<? extends K> c, float f)
c
- a Collection
to be copied into the new hash set.f
- the load factor.public ObjectLinkedOpenHashSet(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 ObjectLinkedOpenHashSet(ObjectCollection<? extends K> c, float f)
c
- a type-specific collection to be copied into the new hash set.f
- the load factor.public ObjectLinkedOpenHashSet(ObjectCollection<? 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 ObjectLinkedOpenHashSet(ObjectIterator<K> i, float f)
i
- a type-specific iterator whose elements will fill the set.f
- the load factor.public ObjectLinkedOpenHashSet(ObjectIterator<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 ObjectLinkedOpenHashSet(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 ObjectLinkedOpenHashSet(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 ObjectLinkedOpenHashSet(K[] a, float f)
a
- an array to be copied into the new hash set.f
- the load factor.public ObjectLinkedOpenHashSet(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.Method Detail |
---|
public void growthFactor(int growthFactor)
growthFactor
- the new growth factor; it must be positive.public int growthFactor()
growthFactor(int)
public boolean add(K k)
add
in interface Collection<K>
add
in interface Set<K>
add
in class AbstractObjectCollection<K>
public boolean remove(Object k)
ObjectSet
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 ObjectSet<K>
remove
in interface Collection<K>
remove
in interface Set<K>
remove
in class AbstractObjectSet<K>
Collection.remove(Object)
public boolean contains(Object k)
contains
in interface Collection<K>
contains
in interface Set<K>
public void clear()
clear
in interface Collection<K>
clear
in interface Set<K>
clear
in class AbstractObjectCollection<K>
public K first()
first
in interface SortedSet<K>
public K last()
last
in interface SortedSet<K>
public ObjectSortedSet<K> tailSet(K from)
ObjectSortedSet
fromElement
.
Note that this specification strengthens the one given in SortedSet.tailSet(Object)
.
tailSet
in interface ObjectSortedSet<K>
tailSet
in interface SortedSet<K>
SortedSet.tailSet(Object)
public ObjectSortedSet<K> headSet(K to)
ObjectSortedSet
toElement
.
Note that this specification strengthens the one given in SortedSet.headSet(Object)
.
headSet
in interface ObjectSortedSet<K>
headSet
in interface SortedSet<K>
SortedSet.headSet(Object)
public ObjectSortedSet<K> subSet(K from, K to)
ObjectSortedSet
fromElement
, inclusive, to toElement
, exclusive.
Note that this specification strengthens the one given in SortedSet.subSet(Object,Object)
.
subSet
in interface ObjectSortedSet<K>
subSet
in interface SortedSet<K>
SortedSet.subSet(Object,Object)
public Comparator<? super K> comparator()
comparator
in interface SortedSet<K>
public ObjectBidirectionalIterator<K> iterator(K from)
This method provides an iterator positioned immediately after the
given element. That is, the next call to previous()
will
return from
, whereas the next call to next()
will return the element immediately after from
. This
allows to call iterator(last())
and obtain an iterator starting
from the end of the iteration order.
Because of the way linking is implemented, generating an iterator using this method
requires constant time only if the argument is last()
. In all other cases,
a linear search for the given element will be necessary.
Note that this method returns a bidirectional iterator, which, however, can be safely cast to a type-specific list iterator.
iterator
in interface ObjectSortedSet<K>
from
- an element to start from.
IllegalArgumentException
- if from
does not belong to the set.public ObjectBidirectionalIterator<K> iterator()
ObjectCollection
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 ObjectCollection<K>
iterator
in interface ObjectIterable<K>
iterator
in interface ObjectSet<K>
iterator
in interface ObjectSortedSet<K>
iterator
in interface Iterable<K>
iterator
in interface Collection<K>
iterator
in interface Set<K>
iterator
in class AbstractObjectSortedSet<K>
public boolean rehash()
This method should be called when the set underwent numerous deletions and insertions. In this case, free entries become rare, and unsuccessful searches require probing all entries. For reasonable load factors this method is linear in the number of entries. You will need as much additional free memory as that occupied by the table.
If you need to reduce the table siza to fit exactly
this set, you must 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 (by collecting deleted entries) and size.
If the table size is already the minimum possible, this method
does nothing. If you want to guarantee rehashing, use rehash()
.
trim(int)
,
rehash()
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()
,
rehash()
public int size()
size
in interface Collection<K>
size
in interface Set<K>
public boolean isEmpty()
isEmpty
in interface Collection<K>
isEmpty
in interface Set<K>
isEmpty
in class AbstractObjectCollection<K>
public Object 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.
clone
in class Object
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 AbstractObjectSet<K>
|
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