public class ObjectLinkedOpenHashSet<K> extends AbstractObjectSortedSet<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, 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(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 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(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(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(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.
|
Comparator<? super K> |
comparator()
This implementation just returns
null. |
boolean |
contains(Object k) |
K |
first()
Returns the first element of this set in iteration order.
|
K |
get(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.
|
boolean |
remove(Object k) |
K |
removeFirst()
Removes the first key in iteration order.
|
K |
removeLast()
Removes the the last key in iteration order.
|
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.
|
equalstoStringcontainsAll, removeAll, retainAll, toArray, toArrayspliteratorcontainsAll, equals, removeAll, retainAll, toArray, toArrayparallelStream, removeIf, streampublic 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(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(Iterator<? extends K> i, float f)
i - a type-specific iterator whose elements will fill the set.f - the load factor.public ObjectLinkedOpenHashSet(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 boolean addAll(Collection<? extends K> c)
addAll in interface Collection<K>addAll in interface Set<K>addAll in class AbstractCollection<K>public boolean add(K k)
add in interface Collection<K>add in interface Set<K>add in class AbstractCollection<K>public K addOrGet(K k)
K exist = set.get(k);
if (exist == null) {
set.add(k);
exist = k;
}
public boolean remove(Object k)
remove in interface Collection<K>remove in interface Set<K>remove in class AbstractCollection<K>public boolean contains(Object k)
contains in interface Collection<K>contains in interface Set<K>contains in class AbstractCollection<K>public K get(Object k)
null.null.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 AbstractCollection<K>public K first()
public K last()
public ObjectSortedSet<K> tailSet(K from)
fromElement.
Note that this specification strengthens the one given in SortedSet.headSet(Object).
This implementation just throws an UnsupportedOperationException.
tailSet in interface ObjectSortedSet<K>tailSet in interface SortedSet<K>SortedSet.tailSet(Object)public ObjectSortedSet<K> headSet(K to)
toElement.
Note that this specification strengthens the one given in SortedSet.headSet(Object).
This implementation just throws an UnsupportedOperationException.
headSet in interface ObjectSortedSet<K>headSet in interface SortedSet<K>SortedSet.headSet(Object)public ObjectSortedSet<K> subSet(K from, K to)
fromElement, inclusive, to toElement, exclusive.
Note that this specification strengthens the one given in SortedSet.subSet(Object,Object).
This implementation just throws an UnsupportedOperationException.
subSet in interface ObjectSortedSet<K>subSet in interface SortedSet<K>SortedSet.subSet(Object,Object)public Comparator<? super K> comparator()
This implementation just returns null.
comparator in interface SortedSet<K>public ObjectListIterator<K> iterator(K from)
iterator in interface ObjectSortedSet<K>from - an element to start from.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 Iterable<K>iterator in interface Collection<K>iterator in interface Set<K>iterator in class AbstractObjectSortedSet<K>Iterable.iterator()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.
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>