Package org.gbif.utils.collection

Class CompactHashSet<T>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<T>

org.gbif.utils.collection.CompactHashSet<T>

All Implemented Interfaces:

Iterable<T>, Collection<T>, Set<T>

public class CompactHashSet<T>
extends AbstractSet<T>

A HashSet implementation taken from Ontopia which is both faster and more compact than java.util.HashSet

INTERNAL: Implements the Set interface more compactly than java.util.HashSet by using a closed hashtable.

See Also:

• Ontopia blog
• Ontopia source

Constructor Summary

Constructors

Constructor	Description
CompactHashSet()	Constructs a new, empty set.
CompactHashSet(int size)	Constructs a new, empty set.
CompactHashSet(Collection c)	Constructs a new set containing the elements in the specified collection.

Method Summary

Modifier and Type	Method	Description
boolean	add(T x)	Adds the specified element to this set if it is not already present.
void	clear()	Removes all of the elements from this set.
boolean	contains(Object o)	Returns true if this set contains the specified element.
void	dump()	INTERNAL: Used for debugging only.
boolean	isEmpty()	Returns true if this set contains no elements.
Iterator	iterator()	Returns an iterator over the elements in this set.
boolean	remove(Object o)	Removes the specified element from the set.
int	size()	Returns the number of elements in this set (its cardinality).
Object[]	toArray()
Object[]	toArray(Object[] a)

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, retainAll, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Set

addAll, containsAll, retainAll, spliterator

Constructor Details

CompactHashSet

public CompactHashSet()

Constructs a new, empty set.

CompactHashSet

public CompactHashSet(Collection c)

Constructs a new set containing the elements in the specified collection.

Parameters:

c - the collection whose elements are to be placed into this set.

CompactHashSet

public CompactHashSet(int size)

Constructs a new, empty set.

Method Details

add

public boolean add(T x)

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

Specified by:

add in interface Collection<T>

Specified by:

add in interface Set<T>

Overrides:

add in class AbstractCollection<T>

Parameters:

x - element to be added to this set.

Returns:

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

clear

public void clear()

Removes all of the elements from this set.

Specified by:

clear in interface Collection<T>

Specified by:

clear in interface Set<T>

Overrides:

clear in class AbstractCollection<T>

contains

public boolean contains(Object o)

Returns true if this set contains the specified element.

Specified by:

contains in interface Collection<T>

Specified by:

contains in interface Set<T>

Overrides:

contains in class AbstractCollection<T>

Parameters:

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

Returns:

true if this set contains the specified element.

dump

public void dump()

INTERNAL: Used for debugging only.

isEmpty

public boolean isEmpty()

Returns true if this set contains no elements.

Specified by:

isEmpty in interface Collection<T>

Specified by:

isEmpty in interface Set<T>

Overrides:

isEmpty in class AbstractCollection<T>

iterator

public Iterator iterator()

Returns an iterator over the elements in this set. The elements are returned in no particular order.

Specified by:

iterator in interface Collection<T>

Specified by:

iterator in interface Iterable<T>

Specified by:

iterator in interface Set<T>

Specified by:

iterator in class AbstractCollection<T>

Returns:

an Iterator over the elements in this set.

See Also:

• ConcurrentModificationException

remove

public boolean remove(Object o)

Removes the specified element from the set.

Specified by:

remove in interface Collection<T>

Specified by:

remove in interface Set<T>

Overrides:

remove in class AbstractCollection<T>

size

public int size()

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

Specified by:

size in interface Collection<T>

Specified by:

size in interface Set<T>

Specified by:

size in class AbstractCollection<T>

toArray

public Object[] toArray()

Specified by:

toArray in interface Collection<T>

Specified by:

toArray in interface Set<T>

Overrides:

toArray in class AbstractCollection<T>

toArray

public Object[] toArray(Object[] a)

Specified by:

toArray in interface Collection<T>

Specified by:

toArray in interface Set<T>

Overrides:

toArray in class AbstractCollection<T>