com.bstek.dorado.util

Class WeakHashSet<E>

java.lang.Object

com.bstek.dorado.util.WeakHashSet<E>

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>, java.util.Set<E>

public class WeakHashSet<E>
extends java.lang.Object
implements java.util.Set<E>

弱引用HashSet。

WeakHashSet的作用类似与WeakHashMap，它不会阻止被引用的对象被GC回收。 并且WeakHashSet会自动的剔除掉那些已被GC回收的引用，因此WeakHashSet是会自动收缩的。

Since:

Feb 19, 2007

Author:

Benny Bao (mailto:benny.bao@bstek.com)

See Also:

WeakHashMap

Constructor Summary

Constructors

Constructor and Description
WeakHashSet()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(E o) Adds the specified element to this set if it is not already present (optional operation).
boolean	addAll(java.util.Collection<? extends E> c) Adds all of the elements in the specified collection to this set if they're not already present (optional operation).
void	clear() Removes all of the elements from this set (optional operation).
boolean	contains(java.lang.Object o) Returns true if this set contains the specified element.
boolean	containsAll(java.util.Collection<?> c) Returns true if this set contains all of the elements of the specified collection.
boolean	isEmpty() Returns true if this set contains no elements.
java.util.Iterator<E>	iterator() Returns an iterator over the elements in this set.
boolean	remove(java.lang.Object o) Removes the specified element from this set if it is present (optional operation).
boolean	removeAll(java.util.Collection<?> c) Removes from this set all of its elements that are contained in the specified collection (optional operation).
boolean	retainAll(java.util.Collection<?> c) Retains only the elements in this set that are contained in the specified collection (optional operation).
int	size() Returns the number of elements in this set (its cardinality).
java.lang.Object[]	toArray() Returns an array containing all of the elements in this set.
<T> T[]	toArray(T[] a) Returns an array containing all of the elements in this set; the runtime type of the returned array is that of the specified array.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Set

equals, hashCode

Constructor Detail

WeakHashSet

public WeakHashSet()

Method Detail

size

public int size()

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

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in interface java.util.Set<E>

Returns:

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

clear

public void clear()

Removes all of the elements from this set (optional operation).

Specified by:

clear in interface java.util.Collection<E>

Specified by:

clear in interface java.util.Set<E>

isEmpty

public boolean isEmpty()

Returns true if this set contains no elements.

Specified by:

isEmpty in interface java.util.Collection<E>

Specified by:

isEmpty in interface java.util.Set<E>

Returns:

true if this set contains no elements.

add

public boolean add(E o)

Adds the specified element to this set if it is not already present (optional operation).

Specified by:

add in interface java.util.Collection<E>

Specified by:

add in interface java.util.Set<E>

Parameters:

o - element to be added to this set.

Returns:

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

contains

public boolean contains(java.lang.Object o)

Returns true if this set contains the specified element.

Specified by:

contains in interface java.util.Collection<E>

Specified by:

contains in interface java.util.Set<E>

Parameters:

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

Returns:

true if this set contains the specified element.

remove

public boolean remove(java.lang.Object o)

Removes the specified element from this set if it is present (optional operation).

Specified by:

remove in interface java.util.Collection<E>

Specified by:

remove in interface java.util.Set<E>

Parameters:

o - object to be removed from this set, if present.

Returns:

true if the set contained the specified element.

addAll

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

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

Specified by:

addAll in interface java.util.Collection<E>

Specified by:

addAll in interface java.util.Set<E>

Parameters:

c - collection whose elements are to be added to this set.

Returns:

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

containsAll

public boolean containsAll(java.util.Collection<?> c)

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

Specified by:

containsAll in interface java.util.Collection<E>

Specified by:

containsAll in interface java.util.Set<E>

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.

removeAll

public boolean removeAll(java.util.Collection<?> c)

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

Specified by:

removeAll in interface java.util.Collection<E>

Specified by:

removeAll in interface java.util.Set<E>

Parameters:

c - collection that defines which elements will be removed from this set.

Returns:

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

retainAll

public boolean retainAll(java.util.Collection<?> c)

Retains only the elements in this set that are contained in the specified collection (optional operation).

Specified by:

retainAll in interface java.util.Collection<E>

Specified by:

retainAll in interface java.util.Set<E>

Parameters:

c - collection that defines which elements this set will retain.

Returns:

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

iterator

public java.util.Iterator<E> iterator()

Returns an iterator over the elements in this set.

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in interface java.util.Set<E>

Returns:

an iterator over the elements in this set.

toArray

public java.lang.Object[] toArray()

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

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.Set<E>

Returns:

an array containing all of the elements in this set.

toArray

public <T> T[] toArray(T[] a)

Returns an array containing all of the elements in this set; the runtime type of the returned array is that of the specified array.

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.Set<E>

Parameters:

a - the array into which the elements of this set are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Returns:

an array containing the elements of this set.