org.apache.commons.collections.bag
Class TransformedBag

java.lang.Object
  org.apache.commons.collections.collection.AbstractCollectionDecorator<E>
      org.apache.commons.collections.collection.AbstractSerializableCollectionDecorator
          org.apache.commons.collections.collection.TransformedCollection
              org.apache.commons.collections.bag.TransformedBag

All Implemented Interfaces:

Serializable, Iterable, Collection, Bag

Direct Known Subclasses:

TransformedSortedBag

public class TransformedBag
extends TransformedCollection
implements Bag

Decorates another Bag to transform objects that are added.

The add methods are affected by this class. Thus objects must be removed or searched for using their transformed form. For example, if the transformation converts Strings to Integers, you must use the Integer form to remove objects.

This class is Serializable from Commons Collections 3.1.

Note: This class cannot support generics without breaking the Collection contract.

Since:

Commons Collections 3.0

Version:

$Revision: 1.2 $ $Date: 2005/05/23 14:42:13 $

Author:

Stephen Colebourne

See Also:

Serialized Form

Field Summary

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

transformer

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

collection

Constructor Summary

protected

TransformedBag(Bag bag, Transformer transformer) Constructor that wraps (not copies).

Method Summary

boolean	add(Object object, int nCopies) Adds nCopies copies of the specified object to the Bag.
static <I,O> Bag<O>	decorate(Bag<I> bag, Transformer<? super I,? extends O> transformer) Factory method to create a transforming bag.
protected Bag	getBag() Gets the decorated bag.
int	getCount(Object object) Returns the number of occurrences (cardinality) of the given object currently in the bag.
boolean	remove(Object object, int nCopies) Removes nCopies copies of the specified object from the Bag.
Set	uniqueSet() Returns a Set of unique elements in the Bag.

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

add, addAll, addAllTyped, addTyped, decorate, transform, transform

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

clear, contains, containsAll, equals, getCollection, 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

TransformedBag

protected TransformedBag(Bag bag,
                         Transformer transformer)

Constructor that wraps (not copies).

If there are any elements already in the bag being decorated, they are NOT transformed.

Parameters:

bag - the bag to decorate, must not be null

transformer - the transformer to use for conversion, must not be null

Throws:

IllegalArgumentException - if bag or transformer is null

Method Detail

decorate

public static <I,O> Bag<O> decorate(Bag<I> bag,
                                    Transformer<? super I,? extends O> transformer)

Factory method to create a transforming bag.

If there are any elements already in the bag being decorated, they are NOT transformed.

Parameters:

bag - the bag to decorate, must not be null

transformer - the transformer to use for conversion, must not be null

Returns:

a new transformed Bag

Throws:

IllegalArgumentException - if bag or transformer is null

getBag

protected Bag getBag()

Gets the decorated bag.

Returns:

the decorated bag

getCount

public int getCount(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

remove

public boolean remove(Object object,
                      int nCopies)

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

nCopies - the number of copies to remove

Returns:

true if this call changed the collection

add

public boolean add(Object object,
                   int nCopies)

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

nCopies - the number of copies to add

Returns:

true if the object was not already in the uniqueSet

uniqueSet

public 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