org.apache.commons.collections.bag
Class SynchronizedBag<E>

java.lang.Object
  org.apache.commons.collections.collection.SynchronizedCollection<E>
      org.apache.commons.collections.bag.SynchronizedBag<E>

All Implemented Interfaces:

Serializable, Iterable<E>, Collection<E>, Bag<E>

Direct Known Subclasses:

SynchronizedSortedBag

public class SynchronizedBag<E>
extends SynchronizedCollection<E>
implements Bag<E>

Decorates another Bag to synchronize its behaviour for a multi-threaded environment.

Methods are synchronized, then forwarded to the decorated bag. Iterators must be separately synchronized around the loop.

This class is Serializable from Commons Collections 3.1.

Since:

Commons Collections 3.0

Version:

$Revision: 1.1.1.1 $ $Date: 2005/05/23 04:33:30 $

Author:

Matt Hall, John Watkinson, Stephen Colebourne

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.commons.collections.collection.SynchronizedCollection

collection, lock

Constructor Summary

protected	SynchronizedBag(Bag<E> bag) Constructor that wraps (not copies).
protected	SynchronizedBag(Bag<E> bag, Object lock) Constructor that wraps (not copies).

Method Summary

boolean	add(E object, int count) Adds nCopies copies of the specified object to the Bag.
static <E> Bag<E>	decorate(Bag<E> bag) Factory method to create a synchronized bag.
protected Bag<E>	getBag() Gets the bag being decorated.
int	getCount(E object) Returns the number of occurrences (cardinality) of the given object currently in the bag.
boolean	remove(E object, int count) Removes nCopies copies of the specified object from the Bag.
Set<E>	uniqueSet() Returns a Set of unique elements in the Bag.

Methods inherited from class org.apache.commons.collections.collection.SynchronizedCollection

add, addAll, clear, contains, containsAll, decorate, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.collections.Bag

add, containsAll, iterator, remove, removeAll, retainAll, size

Methods inherited from interface java.util.Collection

addAll, clear, contains, equals, hashCode, isEmpty, toArray, toArray

Constructor Detail

SynchronizedBag

protected SynchronizedBag(Bag<E> bag)

Constructor that wraps (not copies).

Parameters:

bag - the bag to decorate, must not be null

Throws:

IllegalArgumentException - if bag is null

SynchronizedBag

protected SynchronizedBag(Bag<E> bag,
                          Object lock)

Constructor that wraps (not copies).

Parameters:

bag - the bag to decorate, must not be null

lock - the lock to use, must not be null

Throws:

IllegalArgumentException - if bag is null

Method Detail

decorate

public static <E> Bag<E> decorate(Bag<E> bag)

Factory method to create a synchronized bag.

Parameters:

bag - the bag to decorate, must not be null

Returns:

a new synchronized Bag

Throws:

IllegalArgumentException - if bag is null

getBag

protected Bag<E> getBag()

Gets the bag being decorated.

Returns:

the decorated bag

add

public boolean add(E object,
                   int count)

Description copied from interface: Bag

Adds nCopies copies of the specified object to the Bag.

If the object is already in the Bag.uniqueSet() then increment its count as reported by Bag.getCount(Object). Otherwise add it to the Bag.uniqueSet() and report its count as nCopies.

Specified by:

add in interface Bag<E>

Parameters:

object - the object to add

count - the number of copies to add

Returns:

true if the object was not already in the uniqueSet

remove

public boolean remove(E object,
                      int count)

Description copied from interface: Bag

Removes nCopies copies of the specified object from the Bag.

If the number of copies to remove is greater than the actual number of copies in the Bag, no error is thrown.

Specified by:

remove in interface Bag<E>

Parameters:

object - the object to remove

count - the number of copies to remove

Returns:

true if this call changed the collection

uniqueSet

public Set<E> uniqueSet()

Description copied from interface: Bag

Returns a Set of unique elements in the Bag.

Uniqueness constraints are the same as those in Set.

Specified by:

uniqueSet in interface Bag<E>

Returns:

the Set of unique Bag elements

getCount

public int getCount(E object)

Description copied from interface: Bag

Returns the number of occurrences (cardinality) of the given object currently in the bag. If the object does not exist in the bag, return 0.

Specified by:

getCount in interface Bag<E>

Parameters:

object - the object to search for

Returns:

the number of occurrences of the object, zero if not found