public class PredicatedBag extends PredicatedCollection implements Bag
Bag
to validate that additions
match a specified predicate.
This bag exists to provide validation for the decorated bag. It is normally created to decorate an empty bag. If an object cannot be added to the bag, an IllegalArgumentException is thrown.
One usage would be to ensure that no null entries are added to the bag.
Bag bag = PredicatedBag.decorate(new HashBag(), NotNullPredicate.INSTANCE);
This class is Serializable from Commons Collections 3.1.
Modifier and Type | Method and Description |
---|---|
boolean |
add(java.lang.Object object,
int count)
Adds
nCopies copies of the specified object to the Bag. |
static Bag |
decorate(Bag bag,
Predicate predicate)
Factory method to create a predicated (validating) bag.
|
int |
getCount(java.lang.Object object)
Returns the number of occurrences (cardinality) of the given
object currently in the bag.
|
boolean |
remove(java.lang.Object object,
int count)
Removes
nCopies copies of the specified object from the Bag. |
java.util.Set |
uniqueSet()
Returns a
Set of unique elements in the Bag. |
add, addAll, decorate
clear, contains, containsAll, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray, toString
add, containsAll, iterator, remove, removeAll, retainAll, size
public static Bag decorate(Bag bag, Predicate predicate)
If there are any elements already in the bag being decorated, they are validated.
bag
- the bag to decorate, must not be nullpredicate
- the predicate to use for validation, must not be nulljava.lang.IllegalArgumentException
- if bag or predicate is nulljava.lang.IllegalArgumentException
- if the bag contains invalid elementspublic boolean add(java.lang.Object object, int count)
Bag
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
.
public boolean remove(java.lang.Object object, int count)
Bag
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.
public java.util.Set uniqueSet()
Bag
Set
of unique elements in the Bag.
Uniqueness constraints are the same as those in Set
.
public int getCount(java.lang.Object object)
Bag
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