it.unimi.dsi.fastutil.chars
Class CharLinkedOpenHashSet

java.lang.Object
  java.util.AbstractCollection<Character>
      it.unimi.dsi.fastutil.chars.AbstractCharCollection
          it.unimi.dsi.fastutil.chars.AbstractCharSet
              it.unimi.dsi.fastutil.chars.AbstractCharSortedSet
                  it.unimi.dsi.fastutil.chars.CharLinkedOpenHashSet

All Implemented Interfaces:

CharCollection, CharIterable, CharSet, CharSortedSet, Hash, Serializable, Cloneable, Iterable<Character>, Collection<Character>, Set<Character>, SortedSet<Character>

public class CharLinkedOpenHashSet
extends AbstractCharSortedSet
implements Serializable, Cloneable, Hash

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 by doubling its size 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.

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 AbstractCharSortedSet.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:

Hash, HashCommon, Serialized Form

Nested 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

CharLinkedOpenHashSet()
Creates a new hash set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.

CharLinkedOpenHashSet(char[] a)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.

CharLinkedOpenHashSet(char[] a, float f)
Creates a new hash set copying the elements of an array.

CharLinkedOpenHashSet(char[] 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.

CharLinkedOpenHashSet(char[] a, int offset, int length, float f)
Creates a new hash set and fills it with the elements of a given array.

CharLinkedOpenHashSet(CharCollection c)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection.

CharLinkedOpenHashSet(CharCollection c, float f)
Creates a new hash set copying a given type-specific collection.

CharLinkedOpenHashSet(CharIterator i)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator.

CharLinkedOpenHashSet(CharIterator i, float f)
Creates a new hash set using elements provided by a type-specific iterator.

CharLinkedOpenHashSet(Collection<? extends Character> c)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.

CharLinkedOpenHashSet(Collection<? extends Character> c, float f)
Creates a new hash set copying a given collection.

CharLinkedOpenHashSet(int expected)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.

CharLinkedOpenHashSet(int expected, float f)
Creates a new hash set.

CharLinkedOpenHashSet(Iterator<?> i)
Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by an iterator.

CharLinkedOpenHashSet(Iterator<?> i, float f)
Creates a new hash set using elements provided by an iterator.

Method Summary

boolean	add(char k)
boolean	addAndMoveToFirst(char 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(char 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()
CharLinkedOpenHashSet	clone() Returns a deep copy of this set.
CharComparator	comparator() Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.
boolean	contains(char k)
char	firstChar() 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.
CharSortedSet	headSet(char to)
boolean	isEmpty()
CharListIterator	iterator() Returns a type-specific iterator on the elements of this collection.
CharListIterator	iterator(char from) Returns a type-specific list iterator on the elements in this set, starting from a given element of the set.
char	lastChar() Returns the last element of this set in iteration order.
boolean	rehash() Deprecated. A no-op.
boolean	remove(char k) Removes an element from this set.
char	removeFirstChar() Removes the first key in iteration order.
char	removeLastChar() Removes the the last key in iteration order.
int	size()
CharSortedSet	subSet(char from, char to)
CharSortedSet	tailSet(char from)
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.chars.AbstractCharSortedSet

charIterator, first, headSet, last, subSet, tailSet

Methods inherited from class it.unimi.dsi.fastutil.chars.AbstractCharSet

equals, rem, remove

Methods inherited from class it.unimi.dsi.fastutil.chars.AbstractCharCollection

add, addAll, addAll, contains, containsAll, containsAll, rem, removeAll, removeAll, retainAll, retainAll, toArray, toArray, toArray, toCharArray, toCharArray, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.chars.CharCollection

addAll, containsAll, rem, removeAll, retainAll, toArray, toArray, toCharArray, toCharArray

Methods inherited from interface java.util.Set

add, addAll, contains, containsAll, equals, remove, removeAll, retainAll, toArray, toArray

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(int expected,
                             float f)

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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(int expected)

Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.

Parameters:

expected - the expected number of elements in the hash set.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet()

Creates a new hash set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(Collection<? extends Character> c,
                             float f)

Creates a new hash set copying a given collection.

Parameters:

c - a Collection to be copied into the new hash set.

f - the load factor.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(Collection<? extends Character> c)

Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.

Parameters:

c - a Collection to be copied into the new hash set.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(CharCollection c,
                             float f)

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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(CharCollection c)

Creates a new hash set with Hash.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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(CharIterator i,
                             float f)

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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(CharIterator i)

Creates a new hash set with Hash.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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(Iterator<?> i,
                             float f)

Creates a new hash set using elements provided by an iterator.

Parameters:

i - an iterator whose elements will fill the set.

f - the load factor.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(Iterator<?> i)

Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by an iterator.

Parameters:

i - an iterator whose elements will fill the set.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(char[] a,
                             int offset,
                             int length,
                             float f)

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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(char[] 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.

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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(char[] a,
                             float f)

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.

CharLinkedOpenHashSet

public CharLinkedOpenHashSet(char[] a)

Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.

Parameters:

a - an array to be copied into the new hash set.

Method Detail

add

public boolean add(char k)

Specified by:

add in interface CharCollection

Overrides:

add in class AbstractCharCollection

See Also:

Collection.add(Object)

remove

public boolean remove(char k)

Description copied from interface: CharSet

Removes an element from this set.

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.

Specified by:

remove in interface CharSet

Overrides:

remove in class AbstractCharSet

See Also:

Collection.remove(Object)

contains

public boolean contains(char k)

Specified by:

contains in interface CharCollection

Overrides:

contains in class AbstractCharCollection

See Also:

Collection.contains(Object)

removeFirstChar

public char removeFirstChar()

Removes the first key in iteration order.

Returns:

the first key.

Throws:

NoSuchElementException - is this set is empty.

removeLastChar

public char removeLastChar()

Removes the the last key in iteration order.

Returns:

the last key.

Throws:

NoSuchElementException - is this set is empty.

addAndMoveToFirst

public boolean addAndMoveToFirst(char k)

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.

addAndMoveToLast

public boolean addAndMoveToLast(char k)

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.

clear

public void clear()

Specified by:

clear in interface Collection<Character>

Specified by:

clear in interface Set<Character>

Overrides:

clear in class AbstractCollection<Character>

size

public int size()

Specified by:

size in interface Collection<Character>

Specified by:

size in interface Set<Character>

Specified by:

size in class AbstractCollection<Character>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<Character>

Specified by:

isEmpty in interface Set<Character>

Overrides:

isEmpty in class AbstractCharCollection

growthFactor

@Deprecated
public void growthFactor(int growthFactor)

Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.

A no-op for backward compatibility.

Parameters:

growthFactor - unused.

growthFactor

@Deprecated
public int growthFactor()

Deprecated. Since fastutil 6.1.0, hash tables are doubled when they are too full.

Gets the growth factor (2).

Returns:

the growth factor of this set, which is fixed (2).

See Also:

growthFactor(int)

firstChar

public char firstChar()

Returns the first element of this set in iteration order.

Specified by:

firstChar in interface CharSortedSet

Returns:

the first element in iteration order.

See Also:

SortedSet.first()

lastChar

public char lastChar()

Returns the last element of this set in iteration order.

Specified by:

lastChar in interface CharSortedSet

Returns:

the last element in iteration order.

See Also:

SortedSet.last()

tailSet

public CharSortedSet tailSet(char from)

Specified by:

tailSet in interface CharSortedSet

See Also:

SortedSet.tailSet(Object)

headSet

public CharSortedSet headSet(char to)

Specified by:

headSet in interface CharSortedSet

See Also:

SortedSet.headSet(Object)

subSet

public CharSortedSet subSet(char from,
                            char to)

Specified by:

subSet in interface CharSortedSet

See Also:

SortedSet.subSet(Object,Object)

comparator

public CharComparator comparator()

Description copied from interface: CharSortedSet

Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.

Note that this specification strengthens the one given in SortedSet.comparator().

Specified by:

comparator in interface CharSortedSet

Specified by:

comparator in interface SortedSet<Character>

See Also:

SortedSet.comparator()

iterator

public CharListIterator iterator(char from)

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 interface CharSortedSet

Parameters:

from - an element to start from.

Returns:

a type-specific list iterator starting at the given element.

Throws:

IllegalArgumentException - if from does not belong to the set.

iterator

public CharListIterator iterator()

Description copied from interface: CharCollection

Returns a type-specific iterator on the elements of this collection.

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.

Specified by:

iterator in interface CharCollection

Specified by:

iterator in interface CharIterable

Specified by:

iterator in interface CharSet

Specified by:

iterator in interface CharSortedSet

Specified by:

iterator in interface Iterable<Character>

Specified by:

iterator in interface Collection<Character>

Specified by:

iterator in interface Set<Character>

Specified by:

iterator in class AbstractCharSortedSet

Returns:

a type-specific iterator on the elements of this collection.

rehash

@Deprecated
public boolean rehash()

Deprecated. A no-op.

A no-op for backward compatibility. The kind of tables implemented by this class never need rehashing.

If you need to reduce the table size to fit exactly this set, use trim().

Returns:

true.

See Also:

trim()

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:

trim(int)

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,size()) 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.

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:

trim()

clone

public CharLinkedOpenHashSet 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.

Overrides:

clone in class Object

Returns:

a deep copy of this set.

hashCode

public int hashCode()

Returns a hash code for this set. This method overrides the generic method provided by the superclass. Since 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.

Specified by:

hashCode in interface Collection<Character>

Specified by:

hashCode in interface Set<Character>

Overrides:

hashCode in class AbstractCharSet

Returns:

a hash code for this set.