it.uniroma3.mat.extendedset.intset

Class HashIntSet

java.lang.Object

it.uniroma3.mat.extendedset.intset.AbstractIntSet

it.uniroma3.mat.extendedset.intset.HashIntSet

All Implemented Interfaces:

IntSet, Cloneable, Comparable<IntSet>

public class HashIntSet
extends AbstractIntSet

Implements a fast hash-set.

Inspired by http://code.google.com/p/ontopia/source/browse/trunk/ontopia/src/java/net/ ontopia/utils/CompactHashSet.java

Version:

$Id: HashIntSet.java 156 2011-09-01 00:13:57Z cocciasik $

Author:

Alessandro Colantonio

Nested Class Summary

Nested classes/interfaces inherited from interface it.uniroma3.mat.extendedset.intset.IntSet

IntSet.IntIterator

Field Summary

Fields

Modifier and Type	Field and Description
protected int[]	cells cells
protected static int	EMPTY empty cell
protected int	freecells This is the number of empty cells.
protected static int	INITIAL_SIZE
protected static double	LOAD_FACTOR
protected int	modCount concurrent modification during iteration
protected static int	REMOVED When an object is deleted this object is put into the hashtable in its place, so that other objects with the same key (collisions) further down the hashtable are not lost after we delete an object in the collision chain.
protected int	size number of elements

Constructor Summary

Constructors

Constructor and Description
HashIntSet() Constructs a new, empty set.
HashIntSet(int initialSize) Constructs a new, empty set.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(int element) Adds the specified element to this set if it is not already present.
boolean	addAll(IntSet c) Adds all of the elements in the specified collection to this set if they're not already present.
double	bitmapCompressionRatio() Computes the compression factor of the equivalent bitmap representation (1 means not compressed, namely a memory footprint similar to BitSet, 2 means twice the size of BitSet, etc.)
void	clear() Removes all of the elements from this set.
HashIntSet	clone() See the clone() of Object
double	collectionCompressionRatio() Computes the compression factor of the equivalent integer collection (1 means not compressed, namely a memory footprint similar to ArrayList, 2 means twice the size of ArrayList, etc.)
HashIntSet	complemented() Generates the complement set.
boolean	contains(int element) Returns true if this set contains the specified element.
boolean	containsAll(IntSet c) Returns true if this set contains all of the elements of the specified collection.
boolean	containsAny(IntSet c) Returns true if the specified IntSet instance contains any elements that are also contained within this IntSet instance
boolean	containsAtLeast(IntSet c, int minElements) Returns true if the specified IntSet instance contains at least minElements elements that are also contained within this IntSet instance
HashIntSet	convert(Collection<Integer> c) Converts a given collection into an instance of the current class.
HashIntSet	convert(int... a) Converts a given array into an instance of the current class.
String	debugInfo() Prints debug info about the given IntSet implementation
IntSet.IntIterator	descendingIterator()
HashIntSet	difference(IntSet other) Generates the difference set
HashIntSet	empty() Generates an empty set
boolean	equals(Object obj)
int	first() Returns the first (lowest) element currently in this set.
void	flip(int element) Adds the element if it not existing, or removes it if existing
int	get(int i) Gets the ith element of the set
int	hashCode()
int	indexOf(int e) Provides position of element within the set.
HashIntSet	intersection(IntSet other) Generates the intersection set
int	intersectionSize(IntSet c) Computes the intersection set size.
boolean	isEmpty() Returns true if this set contains no elements.
IntSet.IntIterator	iterator()
int	last() Returns the last (highest) element currently in this set.
protected void	rehash() Figures out correct size for rehashed set, then does the rehash.
protected void	rehash(int newCapacity) Rehashes to a bigger size.
boolean	remove(int element) Removes the specified element from the set.
boolean	removeAll(IntSet c) Removes from this set all of its elements that are contained in the specified collection.
boolean	retainAll(IntSet c) Retains only the elements in this set that are contained in the specified collection.
int	size() Returns the number of elements in this set (its cardinality).
HashIntSet	symmetricDifference(IntSet c) Generates the symmetric difference set
int[]	toArray(int[] a) Returns an array containing all of the elements in this set.
String	toString()
HashIntSet	union(IntSet other) Generates the union set
IntSet.IntIterator	unsortedIterator() Similar to iterator(), but with no particular order

Methods inherited from class it.uniroma3.mat.extendedset.intset.AbstractIntSet

clear, compareTo, complement, complementSize, differenceSize, fill, jaccardDistance, jaccardSimilarity, powerSet, powerSet, powerSetSize, powerSetSize, symmetricDifferenceSize, toArray, unionSize, weightedJaccardDistance, weightedJaccardSimilarity

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

INITIAL_SIZE

protected static final int INITIAL_SIZE

See Also:

Constant Field Values

LOAD_FACTOR

protected static final double LOAD_FACTOR

See Also:

Constant Field Values

EMPTY

protected static final int EMPTY

empty cell

See Also:

Constant Field Values

REMOVED

protected static final int REMOVED

When an object is deleted this object is put into the hashtable in its place, so that other objects with the same key (collisions) further down the hashtable are not lost after we delete an object in the collision chain.

See Also:

Constant Field Values

size

protected int size

number of elements

freecells

protected int freecells

This is the number of empty cells. It's not necessarily the same as objects.length - elements, because some cells may contain REMOVED.

cells

protected int[] cells

cells

modCount

protected int modCount

concurrent modification during iteration

Constructor Detail

HashIntSet

public HashIntSet()

Constructs a new, empty set.

HashIntSet

public HashIntSet(int initialSize)

Constructs a new, empty set.

Parameters:

initialSize -

Method Detail

iterator

public IntSet.IntIterator iterator()

Specified by:

iterator in interface IntSet

Specified by:

iterator in class AbstractIntSet

Returns:

a IntSet.IntIterator instance to iterate over the set

descendingIterator

public IntSet.IntIterator descendingIterator()

Specified by:

descendingIterator in interface IntSet

Specified by:

descendingIterator in class AbstractIntSet

Returns:

a IntSet.IntIterator instance to iterate over the set in descending order

unsortedIterator

public IntSet.IntIterator unsortedIterator()

Similar to iterator(), but with no particular order

Returns:

iterator with no sorting

size

public int size()

Returns the number of elements in this set (its cardinality).

Specified by:

size in interface IntSet

Specified by:

size in class AbstractIntSet

Returns:

the number of elements in this set (its cardinality)

isEmpty

public boolean isEmpty()

Returns true if this set contains no elements.

Specified by:

isEmpty in interface IntSet

Specified by:

isEmpty in class AbstractIntSet

Returns:

true if this set contains no elements

contains

public boolean contains(int element)

Returns true if this set contains the specified element.

Specified by:

contains in interface IntSet

Specified by:

contains in class AbstractIntSet

Parameters:

element - element whose presence in this set is to be tested.

Returns:

true if this set contains the specified element.

add

public boolean add(int element)

Adds the specified element to this set if it is not already present.

Specified by:

add in interface IntSet

Specified by:

add in class AbstractIntSet

Parameters:

element - element to be added to this set.

Returns:

true if the set did not already contain the specified element.

remove

public boolean remove(int element)

Removes the specified element from the set.

Specified by:

remove in interface IntSet

Specified by:

remove in class AbstractIntSet

Parameters:

element - object to be removed from this set, if present

Returns:

true if this set contained the specified element

clear

public void clear()

Removes all of the elements from this set.

Specified by:

clear in interface IntSet

Overrides:

clear in class AbstractIntSet

rehash

protected void rehash()

Figures out correct size for rehashed set, then does the rehash.

rehash

protected void rehash(int newCapacity)

Rehashes to a bigger size.

addAll

public boolean addAll(IntSet c)

Adds all of the elements in the specified collection to this set if they're not already present.

Specified by:

addAll in interface IntSet

Overrides:

addAll in class AbstractIntSet

Parameters:

c - collection containing elements to be added to this set

Returns:

true if this set changed as a result of the call

See Also:

IntSet.add(int)

removeAll

public boolean removeAll(IntSet c)

Removes from this set all of its elements that are contained in the specified collection.

Specified by:

removeAll in interface IntSet

Overrides:

removeAll in class AbstractIntSet

Parameters:

c - collection containing elements to be removed from this set

Returns:

true if this set changed as a result of the call

See Also:

IntSet.remove(int), IntSet.contains(int)

retainAll

public boolean retainAll(IntSet c)

Retains only the elements in this set that are contained in the specified collection. In other words, removes from this set all of its elements that are not contained in the specified collection.

Specified by:

retainAll in interface IntSet

Overrides:

retainAll in class AbstractIntSet

Parameters:

c - collection containing elements to be retained in this set

Returns:

true if this set changed as a result of the call

See Also:

IntSet.remove(int)

clone

public HashIntSet clone()

See the clone() of Object

Specified by:

clone in interface IntSet

Specified by:

clone in class AbstractIntSet

Returns:

cloned object

bitmapCompressionRatio

public double bitmapCompressionRatio()

Computes the compression factor of the equivalent bitmap representation (1 means not compressed, namely a memory footprint similar to BitSet, 2 means twice the size of BitSet, etc.)

Specified by:

bitmapCompressionRatio in interface IntSet

Specified by:

bitmapCompressionRatio in class AbstractIntSet

Returns:

the compression factor

collectionCompressionRatio

public double collectionCompressionRatio()

Computes the compression factor of the equivalent integer collection (1 means not compressed, namely a memory footprint similar to ArrayList, 2 means twice the size of ArrayList, etc.)

Specified by:

collectionCompressionRatio in interface IntSet

Specified by:

collectionCompressionRatio in class AbstractIntSet

Returns:

the compression factor

complemented

public HashIntSet complemented()

Generates the complement set. The returned set is represented by all the elements strictly less than IntSet.last() that do not exist in the current set.

Specified by:

complemented in interface IntSet

Overrides:

complemented in class AbstractIntSet

Returns:

the complement set

See Also:

IntSet.complement()

containsAll

public boolean containsAll(IntSet c)

Returns true if this set contains all of the elements of the specified collection.

Specified by:

containsAll in interface IntSet

Overrides:

containsAll in class AbstractIntSet

Parameters:

c - collection to be checked for containment in this set

Returns:

true if this set contains all of the elements of the specified collection

See Also:

IntSet.contains(int)

containsAny

public boolean containsAny(IntSet c)

Returns true if the specified IntSet instance contains any elements that are also contained within this IntSet instance

Specified by:

containsAny in interface IntSet

Overrides:

containsAny in class AbstractIntSet

Parameters:

c - IntSet to intersect with

Returns:

a boolean indicating whether this IntSet intersects the specified IntSet.

containsAtLeast

public boolean containsAtLeast(IntSet c,
                      int minElements)

Returns true if the specified IntSet instance contains at least minElements elements that are also contained within this IntSet instance

Specified by:

containsAtLeast in interface IntSet

Overrides:

containsAtLeast in class AbstractIntSet

Parameters:

c - IntSet instance to intersect with

minElements - minimum number of elements to be contained within this IntSet instance

Returns:

a boolean indicating whether this IntSet intersects the specified IntSet.

convert

public HashIntSet convert(int... a)

Converts a given array into an instance of the current class.

Specified by:

convert in interface IntSet

Specified by:

convert in class AbstractIntSet

Parameters:

a - array to use to generate the new instance

Returns:

the converted collection

convert

public HashIntSet convert(Collection<Integer> c)

Converts a given collection into an instance of the current class.

Specified by:

convert in interface IntSet

Specified by:

convert in class AbstractIntSet

Parameters:

c - array to use to generate the new instance

Returns:

the converted collection

debugInfo

public String debugInfo()

Prints debug info about the given IntSet implementation

Specified by:

debugInfo in interface IntSet

Specified by:

debugInfo in class AbstractIntSet

Returns:

a string that describes the internal representation of the instance

symmetricDifference

public HashIntSet symmetricDifference(IntSet c)

Generates the symmetric difference set

Specified by:

symmetricDifference in interface IntSet

Overrides:

symmetricDifference in class AbstractIntSet

Parameters:

c - IntSet instance that represents the right operand

Returns:

the result of the operation

See Also:

IntSet.flip(int)

union

public HashIntSet union(IntSet other)

Generates the union set

Specified by:

union in interface IntSet

Overrides:

union in class AbstractIntSet

Parameters:

other - IntSet instance that represents the right operand

Returns:

the result of the operation

See Also:

IntSet.addAll(IntSet)

difference

public HashIntSet difference(IntSet other)

Generates the difference set

Specified by:

difference in interface IntSet

Overrides:

difference in class AbstractIntSet

Parameters:

other - IntSet instance that represents the right operand

Returns:

the result of the operation

See Also:

IntSet.removeAll(IntSet)

intersection

public HashIntSet intersection(IntSet other)

Generates the intersection set

Specified by:

intersection in interface IntSet

Overrides:

intersection in class AbstractIntSet

Parameters:

other - IntSet instance that represents the right operand

Returns:

the result of the operation

See Also:

IntSet.retainAll(IntSet)

empty

public HashIntSet empty()

Generates an empty set

Specified by:

empty in interface IntSet

Specified by:

empty in class AbstractIntSet

Returns:

the empty set

flip

public void flip(int element)

Adds the element if it not existing, or removes it if existing

Specified by:

flip in interface IntSet

Overrides:

flip in class AbstractIntSet

Parameters:

element - element to flip

See Also:

IntSet.symmetricDifference(IntSet)

get

public int get(int i)

Gets the i^th element of the set

Specified by:

get in interface IntSet

Specified by:

get in class AbstractIntSet

Parameters:

i - position of the element in the sorted set

Returns:

the i^th element of the set

indexOf

public int indexOf(int e)

Provides position of element within the set.

It returns -1 if the element does not exist within the set.

Specified by:

indexOf in interface IntSet

Specified by:

indexOf in class AbstractIntSet

Parameters:

e - element of the set

Returns:

the element position

intersectionSize

public int intersectionSize(IntSet c)

Computes the intersection set size.

This is faster than calling IntSet.intersection(IntSet) and then IntSet.size()

Specified by:

intersectionSize in interface IntSet

Overrides:

intersectionSize in class AbstractIntSet

Parameters:

c - IntSet instance that represents the right operand

Returns:

the size

last

public int last()

Returns the last (highest) element currently in this set.

Specified by:

last in interface IntSet

Specified by:

last in class AbstractIntSet

Returns:

the last (highest) element currently in this set

first

public int first()

Returns the first (lowest) element currently in this set.

Specified by:

first in interface IntSet

Overrides:

first in class AbstractIntSet

Returns:

the first (lowest) element currently in this set

toArray

public int[] toArray(int[] a)

Returns an array containing all of the elements in this set.

If this set fits in the specified array with room to spare (i.e., the array has more elements than this set), the element in the array immediately following the end of the set are left unchanged.

Specified by:

toArray in interface IntSet

Overrides:

toArray in class AbstractIntSet

Parameters:

a - the array into which the elements of this set are to be stored.

Returns:

the array containing all the elements in this set

toString

public String toString()

Overrides:

toString in class AbstractIntSet

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractIntSet

equals

public boolean equals(Object obj)

Overrides:

equals in class AbstractIntSet