Package org.apache.commons.collections

Interface Bag

All Superinterfaces:
Collection, Iterable
All Known Subinterfaces:
SortedBag
All Known Implementing Classes:
AbstractBagDecorator, AbstractMapBag, AbstractSortedBagDecorator, DefaultMapBag, HashBag, HashBag, PredicatedBag, PredicatedSortedBag, SynchronizedBag, SynchronizedSortedBag, TransformedBag, TransformedSortedBag, TreeBag, TreeBag, UnmodifiableBag, UnmodifiableSortedBag
@Deprecated(since="2021-04-30") public interface Bag extends Collection
Deprecated.
Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
Defines a collection that counts the number of times an object appears in the collection.

Suppose you have a Bag that contains {a, a, b, c}. Calling getCount(Object) on a would return 2, while calling uniqueSet() would return {a, b, c}.

NOTE: This interface violates the Collection contract. The behavior specified in many of these methods is not the same as the behavior specified by Collection. The noncompliant methods are clearly marked with "(Violation)". Exercise caution when using a bag as a Collection.

This violation resulted from the original specification of this interface. In an ideal world, the interface would be changed to fix the problems, however it has been decided to maintain backwards compatibility instead.

Since:
Commons Collections 2.0

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    add(Object object)
    Deprecated.
    (Violation) Adds one copy the specified object to the Bag.
    boolean
    add(Object object, int nCopies)
    Deprecated.
    Adds nCopies copies of the specified object to the Bag.
    boolean
    containsAll(Collection coll)
    Deprecated.
    (Violation) Returns true if the bag contains all elements in the given collection, respecting cardinality.
    int
    getCount(Object object)
    Deprecated.
    Returns the number of occurrences (cardinality) of the given object currently in the bag.
    Iterator
    iterator()
    Deprecated.
    Returns an Iterator over the entire set of members, including copies due to cardinality.
    boolean
    remove(Object object)
    Deprecated.
    (Violation) Removes all occurrences of the given object from the bag.
    boolean
    remove(Object object, int nCopies)
    Deprecated.
    Removes nCopies copies of the specified object from the Bag.
    boolean
    removeAll(Collection coll)
    Deprecated.
    (Violation) Remove all elements represented in the given collection, respecting cardinality.
    boolean
    retainAll(Collection coll)
    Deprecated.
    (Violation) Remove any members of the bag that are not in the given collection, respecting cardinality.
    int
    size()
    Deprecated.
    Returns the total number of items in the bag across all types.
    Set
    uniqueSet()
    Deprecated.
    Returns a Set of unique elements in the Bag.

    Methods inherited from interface java.util.Collection

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

    Methods inherited from interface java.lang.Iterable

    forEach

  • Method Details

    • getCount

      int getCount(Object object)
      Deprecated.
      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.
      Parameters:
      object - the object to search for
      Returns:
      the number of occurrences of the object, zero if not found

    • add

      boolean add(Object object)
      Deprecated.
      (Violation) Adds one copy the specified object to the Bag.

      If the object is already in the uniqueSet() then increment its count as reported by getCount(Object). Otherwise add it to the uniqueSet() and report its count as 1.

      Since this method always increases the size of the bag, according to the Collection.add(Object) contract, it should always return true. Since it sometimes returns false, this method violates the contract.

      Specified by:
      add in interface Collection
      Parameters:
      object - the object to add
      Returns:
      true if the object was not already in the uniqueSet

    • add

      boolean add(Object object, int nCopies)
      Deprecated.
      Adds nCopies copies of the specified object to the Bag.

      If the object is already in the uniqueSet() then increment its count as reported by getCount(Object). Otherwise add it to the uniqueSet() and report its count as nCopies.

      Parameters:
      object - the object to add
      nCopies - the number of copies to add
      Returns:
      true if the object was not already in the uniqueSet

    • remove

      boolean remove(Object object)
      Deprecated.
      (Violation) Removes all occurrences of the given object from the bag.

      This will also remove the object from the uniqueSet().

      According to the Collection.remove(Object) method, this method should only remove the first occurrence of the given object, not all occurrences.

      Specified by:
      remove in interface Collection
      Returns:
      true if this call changed the collection

    • remove

      boolean remove(Object object, int nCopies)
      Deprecated.
      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.

      Parameters:
      object - the object to remove
      nCopies - the number of copies to remove
      Returns:
      true if this call changed the collection

    • uniqueSet

      Set uniqueSet()
      Deprecated.
      Returns a Set of unique elements in the Bag.

      Uniqueness constraints are the same as those in Set.

      Returns:
      the Set of unique Bag elements

    • size

      int size()
      Deprecated.
      Returns the total number of items in the bag across all types.
      Specified by:
      size in interface Collection
      Returns:
      the total size of the Bag

    • containsAll

      boolean containsAll(Collection coll)
      Deprecated.
      (Violation) Returns true if the bag contains all elements in the given collection, respecting cardinality. That is, if the given collection coll contains n copies of a given object, calling getCount(Object) on that object must be >= n for all n in coll.

      The Collection.containsAll(Collection) method specifies that cardinality should not be respected; this method should return true if the bag contains at least one of every object contained in the given collection.

      Specified by:
      containsAll in interface Collection
      Parameters:
      coll - the collection to check against
      Returns:
      true if the Bag contains all the collection

    • removeAll

      boolean removeAll(Collection coll)
      Deprecated.
      (Violation) Remove all elements represented in the given collection, respecting cardinality. That is, if the given collection coll contains n copies of a given object, the bag will have n fewer copies, assuming the bag had at least n copies to begin with.

      The Collection.removeAll(Collection) method specifies that cardinality should not be respected; this method should remove all occurrences of every object contained in the given collection.

      Specified by:
      removeAll in interface Collection
      Parameters:
      coll - the collection to remove
      Returns:
      true if this call changed the collection

    • retainAll

      boolean retainAll(Collection coll)
      Deprecated.
      (Violation) Remove any members of the bag that are not in the given collection, respecting cardinality. That is, if the given collection coll contains n copies of a given object and the bag has m > n copies, then delete m - n copies from the bag. In addition, if e is an object in the bag but !coll.contains(e), then remove e and any of its copies.

      The Collection.retainAll(Collection) method specifies that cardinality should not be respected; this method should keep all occurrences of every object contained in the given collection.

      Specified by:
      retainAll in interface Collection
      Parameters:
      coll - the collection to retain
      Returns:
      true if this call changed the collection

    • iterator

      Iterator iterator()
      Deprecated.
      Returns an Iterator over the entire set of members, including copies due to cardinality. This iterator is fail-fast and will not tolerate concurrent modifications.
      Specified by:
      iterator in interface Collection
      Specified by:
      iterator in interface Iterable
      Returns:
      iterator over all elements in the Bag