it.unimi.dsi.fastutil.bytes

Class ByteOpenCustomHashSet

java.lang.Object

java.util.AbstractCollection<java.lang.Byte>

it.unimi.dsi.fastutil.bytes.AbstractByteCollection

it.unimi.dsi.fastutil.bytes.AbstractByteSet

it.unimi.dsi.fastutil.bytes.ByteOpenCustomHashSet

All Implemented Interfaces:

ByteCollection, ByteIterable, ByteSet, Hash, java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<java.lang.Byte>, java.util.Collection<java.lang.Byte>, java.util.Set<java.lang.Byte>

public class ByteOpenCustomHashSet
extends AbstractByteSet
implements java.io.Serializable, java.lang.Cloneable, Hash

A type-specific hash set with a fast, small-footprint implementation whose hashing strategy is specified at creation time.

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.

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

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

Constructors

Constructor and Description
ByteOpenCustomHashSet(byte[] a, ByteHash.Strategy strategy) Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.
ByteOpenCustomHashSet(byte[] a, float f, ByteHash.Strategy strategy) Creates a new hash set copying the elements of an array.
ByteOpenCustomHashSet(byte[] a, int offset, int length, ByteHash.Strategy strategy) Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor and fills it with the elements of a given array.
ByteOpenCustomHashSet(byte[] a, int offset, int length, float f, ByteHash.Strategy strategy) Creates a new hash set and fills it with the elements of a given array.
ByteOpenCustomHashSet(ByteCollection c, ByteHash.Strategy strategy) Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection.
ByteOpenCustomHashSet(ByteCollection c, float f, ByteHash.Strategy strategy) Creates a new hash set copying a given type-specific collection.
ByteOpenCustomHashSet(ByteHash.Strategy strategy) Creates a new hash set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.
ByteOpenCustomHashSet(ByteIterator i, ByteHash.Strategy strategy) Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator.
ByteOpenCustomHashSet(ByteIterator i, float f, ByteHash.Strategy strategy) Creates a new hash set using elements provided by a type-specific iterator.
ByteOpenCustomHashSet(java.util.Collection<? extends java.lang.Byte> c, ByteHash.Strategy strategy) Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.
ByteOpenCustomHashSet(java.util.Collection<? extends java.lang.Byte> c, float f, ByteHash.Strategy strategy) Creates a new hash set copying a given collection.
ByteOpenCustomHashSet(int expected, ByteHash.Strategy strategy) Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor.
ByteOpenCustomHashSet(int expected, float f, ByteHash.Strategy strategy) Creates a new hash set.
ByteOpenCustomHashSet(java.util.Iterator<?> i, ByteHash.Strategy strategy) Creates a new hash set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by an iterator.
ByteOpenCustomHashSet(java.util.Iterator<?> i, float f, ByteHash.Strategy strategy) Creates a new hash set using elements provided by an iterator.

Method Summary

Modifier and Type	Method and Description
boolean	add(byte k) Ensures that this collection contains the specified element (optional operation).
boolean	addAll(ByteCollection c) Adds all elements of the given type-specific collection to this collection.
boolean	addAll(java.util.Collection<? extends java.lang.Byte> c)
void	clear()
ByteOpenCustomHashSet	clone() Returns a deep copy of this set.
boolean	contains(byte k) Returns true if this collection contains the specified element.
int	hashCode() Returns a hash code for this set.
boolean	isEmpty()
ByteIterator	iterator() Returns a type-specific iterator on the elements of this collection.
boolean	remove(byte k) Removes an element from this set.
int	size()
ByteHash.Strategy	strategy() Returns the hashing strategy.
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.bytes.AbstractByteSet

equals, rem

Methods inherited from class it.unimi.dsi.fastutil.bytes.AbstractByteCollection

add, contains, containsAll, remove, removeAll, retainAll, toArray, toByteArray, toByteArray, toString

Methods inherited from class java.util.AbstractCollection

containsAll, removeAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.bytes.ByteSet

add, contains, remove

Methods inherited from interface it.unimi.dsi.fastutil.bytes.ByteCollection

containsAll, removeAll, removeIf, removeIf, retainAll, toArray, toByteArray, toByteArray

Methods inherited from interface it.unimi.dsi.fastutil.bytes.ByteIterable

forEach, forEach

Methods inherited from interface java.util.Set

containsAll, removeAll, retainAll, spliterator, toArray, toArray

Methods inherited from interface java.util.Collection

parallelStream, stream

Constructor Detail

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(int expected,
                             float f,
                             ByteHash.Strategy strategy)

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.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(int expected,
                             ByteHash.Strategy strategy)

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

Parameters:

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

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(ByteHash.Strategy strategy)

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

Parameters:

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(java.util.Collection<? extends java.lang.Byte> c,
                             float f,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(java.util.Collection<? extends java.lang.Byte> c,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(ByteCollection c,
                             float f,
                             ByteHash.Strategy 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.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(ByteCollection c,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(ByteIterator i,
                             float f,
                             ByteHash.Strategy 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.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(ByteIterator i,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(java.util.Iterator<?> i,
                             float f,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(java.util.Iterator<?> i,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(byte[] a,
                             int offset,
                             int length,
                             float f,
                             ByteHash.Strategy 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.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(byte[] a,
                             int offset,
                             int length,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(byte[] a,
                             float f,
                             ByteHash.Strategy strategy)

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.

ByteOpenCustomHashSet

public ByteOpenCustomHashSet(byte[] a,
                             ByteHash.Strategy strategy)

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.

strategy - the strategy.

Method Detail

strategy

public ByteHash.Strategy strategy()

Returns the hashing strategy.

Returns:

the hashing strategy of this custom hash set.

addAll

public boolean addAll(ByteCollection c)

Description copied from interface: ByteCollection

Adds all elements of the given type-specific collection to this collection.

Specified by:

addAll in interface ByteCollection

Overrides:

addAll in class AbstractByteCollection

Parameters:

c - a type-specific collection.

Returns:

true if this collection changed as a result of the call.

See Also:

Collection.addAll(Collection)

addAll

public boolean addAll(java.util.Collection<? extends java.lang.Byte> c)

Specified by:

addAll in interface java.util.Collection<java.lang.Byte>

Specified by:

addAll in interface java.util.Set<java.lang.Byte>

Overrides:

addAll in class java.util.AbstractCollection<java.lang.Byte>

add

public boolean add(byte k)

Description copied from class: AbstractByteCollection

Ensures that this collection contains the specified element (optional operation).

This implementation always throws an UnsupportedOperationException.

Specified by:

add in interface ByteCollection

Overrides:

add in class AbstractByteCollection

See Also:

Collection.add(Object)

remove

public boolean remove(byte k)

Description copied from class: AbstractByteSet

Removes an element from this set.

Note that the corresponding method of a type-specific collection is rem(). This unfortunate situation is caused by the clash with the similarly named index-based method in the List interface. Delegates to the type-specific rem() method implemented by type-specific abstract Collection superclass.

Specified by:

remove in interface ByteSet

Overrides:

remove in class AbstractByteSet

See Also:

Collection.remove(Object)

contains

public boolean contains(byte k)

Description copied from class: AbstractByteCollection

Returns true if this collection contains the specified element.

This implementation iterates over the elements in the collection, looking for the specified element.

Specified by:

contains in interface ByteCollection

Overrides:

contains in class AbstractByteCollection

See Also:

Collection.contains(Object)

clear

public void clear()

Specified by:

clear in interface java.util.Collection<java.lang.Byte>

Specified by:

clear in interface java.util.Set<java.lang.Byte>

Overrides:

clear in class java.util.AbstractCollection<java.lang.Byte>

size

public int size()

Specified by:

size in interface java.util.Collection<java.lang.Byte>

Specified by:

size in interface java.util.Set<java.lang.Byte>

Specified by:

size in class java.util.AbstractCollection<java.lang.Byte>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Collection<java.lang.Byte>

Specified by:

isEmpty in interface java.util.Set<java.lang.Byte>

Overrides:

isEmpty in class java.util.AbstractCollection<java.lang.Byte>

iterator

public ByteIterator iterator()

Description copied from interface: ByteCollection

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 ByteCollection

Specified by:

iterator in interface ByteIterable

Specified by:

iterator in interface ByteSet

Specified by:

iterator in interface java.lang.Iterable<java.lang.Byte>

Specified by:

iterator in interface java.util.Collection<java.lang.Byte>

Specified by:

iterator in interface java.util.Set<java.lang.Byte>

Specified by:

iterator in class AbstractByteSet

Returns:

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

See Also:

Iterable.iterator()

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 ByteOpenCustomHashSet 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 java.lang.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 java.util.Collection<java.lang.Byte>

Specified by:

hashCode in interface java.util.Set<java.lang.Byte>

Overrides:

hashCode in class AbstractByteSet

Returns:

a hash code for this set.