org.apache.commons.collections.bag
Class SynchronizedBag

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

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable, java.util.Collection, Bag

Direct Known Subclasses:

SynchronizedSortedBag

public class SynchronizedBag
extends SynchronizedCollection
implements Bag

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: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

Author:

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 bag) Constructor that wraps (not copies).
protected	SynchronizedBag(Bag bag, java.lang.Object lock) Constructor that wraps (not copies).

Method Summary

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

Constructor that wraps (not copies).

Parameters:

bag - the bag to decorate, must not be null

Throws:

java.lang.IllegalArgumentException - if bag is null

SynchronizedBag

protected SynchronizedBag(Bag bag,
                          java.lang.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:

java.lang.IllegalArgumentException - if bag is null

Method Detail

decorate

public static Bag decorate(Bag bag)

Factory method to create a synchronized bag.

Parameters:

bag - the bag to decorate, must not be null

Returns:

a new synchronized Bag

Throws:

java.lang.IllegalArgumentException - if bag is null

getBag

protected Bag getBag()

Gets the bag being decorated.

Returns:

the decorated bag

add

public boolean add(java.lang.Object 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

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(java.lang.Object 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

Parameters:

object - the object to remove

count - the number of copies to remove

Returns:

true if this call changed the collection

uniqueSet

public java.util.Set 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

Returns:

the Set of unique Bag elements

getCount

public int getCount(java.lang.Object 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

Parameters:

object - the object to search for

Returns:

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