org.apache.commons.collections.bag

## Class AbstractBagDecorator

- java.lang.Object
- - org.apache.commons.collections.collection.AbstractCollectionDecorator
  - - org.apache.commons.collections.bag.AbstractBagDecorator

- All Implemented Interfaces:
    Iterable, Collection, Bag
  Direct Known Subclasses:
    AbstractSortedBagDecorator, UnmodifiableBag

      public abstract class AbstractBagDecorator
      extends AbstractCollectionDecorator
      implements Bag

  Decorates another `Bag` to provide additional behaviour.

  Methods are forwarded directly to the decorated bag.

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

- - ### Field Summary

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

      `collection`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `AbstractBagDecorator()` Constructor only used in deserialization, do not use otherwise.
    `protected` | `AbstractBagDecorator(Bag bag)` Constructor that wraps (not copies).

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `add(Object object, int count)` Adds `nCopies` copies of the specified object to the Bag.
    `protected Bag` | `getBag()` Gets the bag being decorated.
    `int` | `getCount(Object object)` Returns the number of occurrences (cardinality) of the given object currently in the bag.
    `boolean` | `remove(Object object, int count)` 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.AbstractCollectionDecorator

      `add, addAll, 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

    - #### AbstractBagDecorator

          protected AbstractBagDecorator()

      Constructor only used in deserialization, do not use otherwise.
      Since:
        Commons Collections 3.1

    - #### AbstractBagDecorator

          protected AbstractBagDecorator(Bag bag)

      Constructor that wraps (not copies).
      Parameters:
        `bag` - the bag to decorate, must not be null
      Throws:
        `IllegalArgumentException` - if list is null

  - ### Method Detail

    - #### getBag

          protected Bag getBag()

      Gets the bag being decorated.
      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

    - #### add

          public boolean add(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(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 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

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