PredicatedBag (Apache Commons Collections 3.2.2 API)

java.lang.Object
- org.apache.commons.collections.collection.AbstractCollectionDecorator
- - org.apache.commons.collections.collection.AbstractSerializableCollectionDecorator
  - - org.apache.commons.collections.collection.PredicatedCollection
    - - org.apache.commons.collections.bag.PredicatedBag

All Implemented Interfaces:

Serializable, Iterable, Collection, Bag

Direct Known Subclasses:

PredicatedSortedBag
```
public class PredicatedBag
extends PredicatedCollection
implements Bag
```
Decorates another 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.
Since:

Commons Collections 3.0

Version:

$Revision: 972404 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne, Paul Jack

See Also:
Serialized Form

Field Summary
- Fields inherited from class org.apache.commons.collections.collection.PredicatedCollection
  predicate
- Fields inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
  collection

Constructor Summary

Constructors
Modifier Constructor and Description

protected PredicatedBag(Bag bag, Predicate predicate)
Constructor that wraps (not copies).

Constructors
Modifier	Constructor and Description
`protected`	`PredicatedBag(Bag bag, Predicate predicate)` 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.
`static Bag`	`decorate(Bag bag, Predicate predicate)` Factory method to create a predicated (validating) bag.
`protected Bag`	`getBag()` Gets the decorated bag.
`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.PredicatedCollection
add, addAll, decorate, validate

Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
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
  - PredicatedBag
```
protected PredicatedBag(Bag bag,
             Predicate predicate)
```
    Constructor that wraps (not copies).
    If there are any elements already in the bag being decorated, they are validated.
    
    Parameters:
    bag - the bag to decorate, must not be null
    predicate - the predicate to use for validation, must not be null
    
    Throws:
    
    IllegalArgumentException - if bag or predicate is null
    
    IllegalArgumentException - if the bag contains invalid elements
- Method Detail
  - decorate
```
public static Bag decorate(Bag bag,
           Predicate predicate)
```
    Factory method to create a predicated (validating) bag.
    If there are any elements already in the bag being decorated, they are validated.
    
    Parameters:
    bag - the bag to decorate, must not be null
    predicate - the predicate to use for validation, must not be null
    
    Returns:
    a new predicated Bag
    
    Throws:
    
    IllegalArgumentException - if bag or predicate is null
    
    IllegalArgumentException - if the bag contains invalid elements
  - getBag
```
protected Bag getBag()
```
    Gets the decorated bag.
    
    Returns:
    the decorated bag
  - 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
  - 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

Class PredicatedBag

Field Summary

Fields inherited from class org.apache.commons.collections.collection.PredicatedCollection

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

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.collections.collection.PredicatedCollection

Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.commons.collections.Bag

Methods inherited from interface java.util.Collection

Constructor Detail

PredicatedBag

Method Detail

decorate

getBag

add

remove

uniqueSet

getCount