Package org.apache.commons.collections4.bag

Class TransformedBag<E>

java.lang.Object

org.apache.commons.collections4.collection.AbstractCollectionDecorator<E>

org.apache.commons.collections4.collection.TransformedCollection<E>

org.apache.commons.collections4.bag.TransformedBag<E>

Type Parameters:

E - the type of elements in this bag

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, Bag<E>

Direct Known Subclasses:

TransformedSortedBag

public class TransformedBag<E>
extends TransformedCollection<E>
implements Bag<E>

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.

Since:

3.0

See Also:

Serialized Form

Method Summary

Modifier and Type	Method	Description
boolean	add(E object, int nCopies)	Adds nCopies copies of the specified object to the Bag.
boolean	equals(java.lang.Object object)
int	getCount(java.lang.Object object)	Returns the number of occurrences (cardinality) of the given object currently in the bag.
int	hashCode()
boolean	remove(java.lang.Object object, int nCopies)	Removes nCopies copies of the specified object from the Bag.
static <E> Bag<E>	transformedBag(Bag<E> bag, Transformer<? super E,? extends E> transformer)	Factory method to create a transforming bag that will transform existing contents of the specified bag.
static <E> Bag<E>	transformingBag(Bag<E> bag, Transformer<? super E,? extends E> transformer)	Factory method to create a transforming bag.
java.util.Set<E>	uniqueSet()	Returns a Set of unique elements in the Bag.

Methods inherited from class org.apache.commons.collections4.collection.TransformedCollection

add, addAll, transformedCollection, transformingCollection

Methods inherited from class org.apache.commons.collections4.collection.AbstractCollectionDecorator

clear, contains, containsAll, isEmpty, iterator, remove, removeAll, removeIf, retainAll, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.commons.collections4.Bag

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

Methods inherited from interface java.util.Collection

addAll, clear, contains, isEmpty, parallelStream, removeIf, spliterator, stream, toArray, toArray, toArray

Methods inherited from interface java.lang.Iterable

forEach

Method Detail

transformingBag

public static <E> Bag<E> transformingBag(Bag<E> bag,
                                         Transformer<? super E,? extends E> transformer)

Factory method to create a transforming bag.

If there are any elements already in the bag being decorated, they are NOT transformed. Contrast this with transformedBag(Bag, Transformer).

Type Parameters:

E - the type of the elements in the bag

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:

java.lang.NullPointerException - if bag or transformer is null

Since:

4.0

transformedBag

public static <E> Bag<E> transformedBag(Bag<E> bag,
                                        Transformer<? super E,? extends E> transformer)

Factory method to create a transforming bag that will transform existing contents of the specified bag.

If there are any elements already in the bag being decorated, they will be transformed by this method. Contrast this with transformingBag(Bag, Transformer).

Type Parameters:

E - the type of the elements in the bag

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:

java.lang.NullPointerException - if bag or transformer is null

Since:

4.0

equals

public boolean equals(java.lang.Object object)

Specified by:

equals in interface java.util.Collection<E>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Collection<E>

Overrides:

hashCode in class java.lang.Object

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<E>

Parameters:

object - the object to search for

Returns:

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

remove

public boolean remove(java.lang.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<E>

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(E 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<E>

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 java.util.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