public class ObjectLinkedOpenHashSet<K> extends AbstractObjectSortedSet<K> implements java.io.Serializable, java.lang.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, 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.
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 |
---|
ObjectLinkedOpenHashSet()
Creates a new hash set with initial expected
Hash.DEFAULT_INITIAL_SIZE elements
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
ObjectLinkedOpenHashSet(java.util.Collection<? extends K> c)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor
copying a given collection. |
ObjectLinkedOpenHashSet(java.util.Collection<? extends K> c,
float f)
Creates a new hash set copying a given collection.
|
ObjectLinkedOpenHashSet(int expected)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
ObjectLinkedOpenHashSet(int expected,
float f)
Creates a new hash set.
|
ObjectLinkedOpenHashSet(java.util.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. |
ObjectLinkedOpenHashSet(java.util.Iterator<? extends K> i,
float f)
Creates a new hash set using elements provided by a type-specific iterator.
|
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.
|
Modifier and Type | Method and Description |
---|---|
boolean |
add(K k) |
boolean |
addAll(java.util.Collection<? extends K> c) |
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.
|
K |
addOrGet(K k)
Add a random element if not present, get the existing value if already present.
|
void |
clear() |
ObjectLinkedOpenHashSet<K> |
clone()
Returns a deep copy of this set.
|
java.util.Comparator<? super K> |
comparator() |
boolean |
contains(java.lang.Object k) |
K |
first()
Returns the first element of this set in iteration order.
|
void |
forEach(java.util.function.Consumer<? super K> action) |
K |
get(java.lang.Object k)
Returns the element of this set that is equal to the given key, or
null . |
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() |
ObjectListIterator<K> |
iterator()
Returns a type-specific list iterator on the elements in this set, starting from the first element.
|
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.
|
static <K> ObjectLinkedOpenHashSet<K> |
of()
Creates a new empty hash set.
|
static <K> ObjectLinkedOpenHashSet<K> |
of(K... a)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor
using a list of elements. |
static <K> ObjectLinkedOpenHashSet<K> |
of(K e)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor
using the given element. |
static <K> ObjectLinkedOpenHashSet<K> |
of(K e0,
K e1)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor
using the elements given. |
static <K> ObjectLinkedOpenHashSet<K> |
of(K e0,
K e1,
K e2)
Creates a new hash set with
Hash.DEFAULT_LOAD_FACTOR as load factor
using the elements given. |
boolean |
remove(java.lang.Object k) |
K |
removeFirst()
Removes the first key in iteration order.
|
K |
removeLast()
Removes the the last key in iteration order.
|
int |
size() |
ObjectSpliterator<K> |
spliterator()
Returns a type-specific spliterator on the elements of this sorted-set.
|
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 . |
static <K> java.util.stream.Collector<K,?,ObjectLinkedOpenHashSet<K>> |
toSet()
Returns a
Collector that collects a Stream 's elements into a new hash set. |
static <K> java.util.stream.Collector<K,?,ObjectLinkedOpenHashSet<K>> |
toSetWithExpectedSize(int expectedSize)
Returns a
Collector that collects a Stream 's elements into a new hash set, potentially pre-allocated to handle the given size. |
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.
|
equals
toString
containsAll, removeAll, retainAll, toArray, toArray
public ObjectLinkedOpenHashSet(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 ObjectLinkedOpenHashSet(int expected)
Hash.DEFAULT_LOAD_FACTOR
as load factor.expected
- 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(java.util.Collection<? extends K> c, float f)
c
- a Collection
to be copied into the new hash set.f
- the load factor.public ObjectLinkedOpenHashSet(java.util.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(java.util.Iterator<? extends K> i, float f)
i
- a type-specific iterator whose elements will fill the set.f
- the load factor.public ObjectLinkedOpenHashSet(java.util.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 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.public static <K> ObjectLinkedOpenHashSet<K> of()
public static <K> ObjectLinkedOpenHashSet<K> of(K e)
Hash.DEFAULT_LOAD_FACTOR
as load factor
using the given element.of
in interface ObjectSet<K>
e
- the element that the returned set will contain.Hash.DEFAULT_LOAD_FACTOR
as load factor containing e
.public static <K> ObjectLinkedOpenHashSet<K> of(K e0, K e1)
Hash.DEFAULT_LOAD_FACTOR
as load factor
using the elements given.of
in interface ObjectSet<K>
e0
- the first element.e1
- the second element.Hash.DEFAULT_LOAD_FACTOR
as load factor containing e0
and e1
.java.lang.IllegalArgumentException
- if there were duplicate entries.public static <K> ObjectLinkedOpenHashSet<K> of(K e0, K e1, K e2)
Hash.DEFAULT_LOAD_FACTOR
as load factor
using the elements given.of
in interface ObjectSet<K>
e0
- the first element.e1
- the second element.e2
- the third element.Hash.DEFAULT_LOAD_FACTOR
as load factor containing e0
, e1
, and e2
.java.lang.IllegalArgumentException
- if there were duplicate entries.@SafeVarargs public static <K> ObjectLinkedOpenHashSet<K> of(K... a)
Hash.DEFAULT_LOAD_FACTOR
as load factor
using a list of elements.of
in interface ObjectSet<K>
a
- a list of elements that will be used to initialize the new hash set.Hash.DEFAULT_LOAD_FACTOR
as load factor containing the elements of a
.java.lang.IllegalArgumentException
- if a duplicate entry was encountered.public static <K> java.util.stream.Collector<K,?,ObjectLinkedOpenHashSet<K>> toSet()
Collector
that collects a Stream
's elements into a new hash set.public static <K> java.util.stream.Collector<K,?,ObjectLinkedOpenHashSet<K>> toSetWithExpectedSize(int expectedSize)
Collector
that collects a Stream
's elements into a new hash set, potentially pre-allocated to handle the given size.public boolean addAll(java.util.Collection<? extends K> c)
public boolean add(K k)
public K addOrGet(K k)
K exist = set.get(k); if (exist == null) { set.add(k); exist = k; }
public boolean remove(java.lang.Object k)
public boolean contains(java.lang.Object k)
public K get(java.lang.Object k)
null
.null
.public K removeFirst()
java.util.NoSuchElementException
- is this set is empty.public K removeLast()
java.util.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()
public int size()
public boolean isEmpty()
public K first()
first
in interface java.util.SortedSet<K>
public K last()
last
in interface java.util.SortedSet<K>
public ObjectSortedSet<K> tailSet(K from)
fromElement
.tailSet
in interface ObjectSortedSet<K>
tailSet
in interface java.util.SortedSet<K>
SortedSet.tailSet(Object)
UnsupportedOperationException
.public ObjectSortedSet<K> headSet(K to)
toElement
.headSet
in interface ObjectSortedSet<K>
headSet
in interface java.util.SortedSet<K>
SortedSet.headSet(Object)
UnsupportedOperationException
.public ObjectSortedSet<K> subSet(K from, K to)
fromElement
, inclusive, to toElement
, exclusive.subSet
in interface ObjectSortedSet<K>
subSet
in interface java.util.SortedSet<K>
SortedSet.subSet(Object,Object)
UnsupportedOperationException
.public java.util.Comparator<? super K> comparator()
comparator
in interface java.util.SortedSet<K>
null
.public ObjectListIterator<K> iterator(K from)
iterator
in interface ObjectSortedSet<K>
from
- an element to start from.java.lang.IllegalArgumentException
- if from
does not belong to the set.public ObjectListIterator<K> iterator()
iterator
in interface ObjectBidirectionalIterable<K>
iterator
in interface ObjectCollection<K>
iterator
in interface ObjectIterable<K>
iterator
in interface ObjectSet<K>
iterator
in interface ObjectSortedSet<K>
iterator
in interface java.lang.Iterable<K>
iterator
in interface java.util.Collection<K>
iterator
in interface java.util.Set<K>
iterator
in class AbstractObjectSortedSet<K>
Iterable.iterator()
public ObjectSpliterator<K> spliterator()
SortedSet spliterators must report at least Spliterator.DISTINCT
,
Spliterator.ORDERED
, and Spliterator.SORTED
. The returned spliterator's
getComparator()
must be the same (or at the very least,
consistent with) this instance's SortedSet.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,
report Spliterator.SORTED
. This is because iteration order is based on insertion
order, not natural ordering.
spliterator
in interface ObjectCollection<K>
spliterator
in interface ObjectIterable<K>
spliterator
in interface ObjectSet<K>
spliterator
in interface ObjectSortedSet<K>
spliterator
in interface java.lang.Iterable<K>
spliterator
in interface java.util.Collection<K>
spliterator
in interface java.util.Set<K>
spliterator
in interface java.util.SortedSet<K>
public void forEach(java.util.function.Consumer<? super K> action)
forEach
in interface java.lang.Iterable<K>
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 ObjectLinkedOpenHashSet<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.
clone
in class java.lang.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 java.util.Collection<K>
hashCode
in interface java.util.Set<K>
hashCode
in class AbstractObjectSet<K>