Package org.geotools.util

Class WeakHashSet<E>

Object

AbstractCollection<E>

AbstractSet<E>

WeakHashSet<E>

Type Parameters:

E - The type of elements in the set.

All Implemented Interfaces:

Iterable<E>, Collection<E>, Set<E>, CheckedCollection<E>

Direct Known Subclasses:

CanonicalSet

public class WeakHashSet<E>
extends AbstractSet<E>
implements CheckedCollection<E>

A set of objects hold by weak references. An entry in a WeakHashSet will automatically be removed when it is no longer in ordinary use. More precisely, the presence of an entry will not prevent the entry from being discarded by the garbage collector, that is, made finalizable, finalized, and then reclaimed. When an entry has been discarded it is effectively removed from the set, so this class behaves somewhat differently than other Set implementations.

If you would like to use WeakHashSet as inside a factory to prevent creating duplicate immutable objects, please look at the CanonicalSet subclass.

The WeakHashSet class is thread-safe.

Since:

2.0

Author:

Martin Desruisseaux (IRD)

See Also:

WeakHashMap

Constructor Summary

Constructors

Constructor	Description
WeakHashSet(Class<E> type)	Constructs a WeakHashSet.

Method Summary

Modifier and Type	Method	Description
boolean	add(E obj)	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 obj)	Returns true if this set contains the specified element.
Class<E>	getElementType()	Returns the element type.
Iterator<E>	iterator()	Returns an iterator over the elements contained in this collection.
boolean	remove(Object obj)	Removes a single instance of the specified element from this set, if it is present
int	size()	Returns the count of element in this set.
E[]	toArray()	Returns a view of this set as an array.

Methods inherited from class AbstractSet

equals, hashCode, removeAll

Methods inherited from class AbstractCollection

addAll, containsAll, isEmpty, retainAll, toArray, toString

Methods inherited from class Object

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

Methods inherited from interface Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface Iterable

forEach

Methods inherited from interface Set

addAll, containsAll, isEmpty, retainAll, spliterator, toArray

Constructor Detail

WeakHashSet

public WeakHashSet(Class<E> type)

Constructs a WeakHashSet.

Parameters:

type - The type of the element to be included in this set.

Since:

2.5

Method Detail

getElementType

public Class<E> getElementType()

Returns the element type.

Specified by:

getElementType in interface CheckedCollection<E>

Returns:

The element type.

Since:

2.5

size

public int size()

Returns the count of element in this set.

Specified by:

size in interface Collection<E>

Specified by:

size in interface Set<E>

Specified by:

size in class AbstractCollection<E>

contains

public boolean contains(Object obj)

Returns true if this set contains the specified element.

Specified by:

contains in interface Collection<E>

Specified by:

contains in interface Set<E>

Overrides:

contains in class AbstractCollection<E>

Parameters:

obj - Object to be checked for containment in this set.

Returns:

true if this set contains the specified element.

remove

public boolean remove(Object obj)

Removes a single instance of the specified element from this set, if it is present

Specified by:

remove in interface Collection<E>

Specified by:

remove in interface Set<E>

Overrides:

remove in class AbstractCollection<E>

Parameters:

obj - element to be removed from this set, if present.

Returns:

true if the set contained the specified element.

add

public boolean add(E obj)

Adds the specified element to this set if it is not already present. If this set already contains the specified element, the call leaves this set unchanged and returns false.

Specified by:

add in interface Collection<E>

Specified by:

add in interface Set<E>

Overrides:

add in class AbstractCollection<E>

Parameters:

obj - Element to be added to this set.

Returns:

true if this 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<E>

Specified by:

clear in interface Set<E>

Overrides:

clear in class AbstractCollection<E>

toArray

public E[] toArray()

Returns a view of this set as an array. Elements will be in an arbitrary order. Note that this array contains strong reference. Consequently, no object reclamation will occurs as long as a reference to this array is hold.

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface Set<E>

Overrides:

toArray in class AbstractCollection<E>

iterator

public Iterator<E> iterator()

Returns an iterator over the elements contained in this collection. No element from this set will be garbage collected as long as a reference to the iterator is hold.

Specified by:

iterator in interface Collection<E>

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Set<E>

Specified by:

iterator in class AbstractCollection<E>