Package org.apache.commons.collections.bag

Class TransformedBag

java.lang.Object
org.apache.commons.collections.collection.AbstractCollectionDecorator
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.

Since:
Commons Collections 3.0
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
Author:
Stephen Colebourne
See Also:

  • Constructor Details

    • 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 Details

    • decorate

      public static Bag decorate(Bag bag, Transformer 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