Package org.apache.commons.collections

Interface Bag

    • Method Detail

      • getCount

        int getCount​(Object object)
        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)
        (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)
        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)
        (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)
        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()
        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()
        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)
        (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)
        (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)
        (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()
        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