| org.apache.commons.collections.Bag
All known Subclasses: org.apache.commons.collections.bag.AbstractMapBag, org.apache.commons.collections.bag.SynchronizedBag, org.apache.commons.collections.bag.HashBag, org.apache.commons.collections.DefaultMapBag, org.apache.commons.collections.bag.AbstractBagDecorator, org.apache.commons.collections.bag.PredicatedBag, org.apache.commons.collections.HashBag, org.apache.commons.collections.bag.TransformedBag,
| Bag | | public interface Bag extends Collection(Code) | | 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
Bag.getCount(Object) on a would return 2, while
calling
Bag.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
version:
$Revision: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $
author:
Chuck Burdick
author:
Stephen Colebourne |
| Method Summary | |
| boolean | add(Object object)
(Violation)
Adds one copy 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) . | | boolean | add(Object object, int nCopies)
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) . | | boolean | containsAll(Collection coll)
(Violation)
Returns true if the bag contains all elements in
the given collection, respecting cardinality. | | int | getCount(Object object)
Returns the number of occurrences (cardinality) of the given
object currently in the bag. | | Iterator | iterator()
Returns an
Iterator over the entire set of members,
including copies due to cardinality. | | boolean | remove(Object object)
(Violation)
Removes all occurrences of the given object from the bag. | | boolean | remove(Object object, int nCopies)
Removes nCopies copies of the specified object from the Bag. | | boolean | removeAll(Collection coll)
(Violation)
Remove all elements represented in the given collection,
respecting cardinality. | | boolean | retainAll(Collection coll)
(Violation)
Remove any members of the bag that are not in the given
collection, respecting cardinality. | | int | size()
Returns the total number of items in the bag across all types. | | Set | uniqueSet()
Returns a
Set of unique elements in the Bag. |
| add | | boolean add(Object object)(Code) | | (Violation)
Adds one copy 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 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.
Parameters:
object - the object to add true if the object was not already in the uniqueSet |
| add | | boolean add(Object object, int nCopies)(Code) | | 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.
Parameters:
object - the object to add
Parameters:
nCopies - the number of copies to add true if the object was not already in the uniqueSet |
| containsAll | | boolean containsAll(Collection coll)(Code) | | (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
Bag.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.
Parameters:
coll - the collection to check against true if the Bag contains all the collection |
| getCount | | int getCount(Object object)(Code) | | 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 the number of occurrences of the object, zero if not found |
| iterator | | Iterator iterator()(Code) | | 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.
iterator over all elements in the Bag |
| remove | | boolean remove(Object object)(Code) | | (Violation)
Removes all occurrences of the given object from the bag.
This will also remove the object from the
Bag.uniqueSet() .
According to the
Collection.remove(Object) method,
this method should only remove the first occurrence of the
given object, not all occurrences.
true if this call changed the collection |
| remove | | boolean remove(Object object, int nCopies)(Code) | | 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
Parameters:
nCopies - the number of copies to remove true if this call changed the collection |
| removeAll | | boolean removeAll(Collection coll)(Code) | | (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.
Parameters:
coll - the collection to remove true if this call changed the collection |
| retainAll | | boolean retainAll(Collection coll)(Code) | | (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.
Parameters:
coll - the collection to retain true if this call changed the collection |
| size | | int size()(Code) | | Returns the total number of items in the bag across all types.
the total size of the Bag |
| uniqueSet | | Set uniqueSet()(Code) | | Returns a
Set of unique elements in the Bag.
Uniqueness constraints are the same as those in
java.util.Set .
the Set of unique Bag elements |
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