org.apache.commons.collections.bag
Class UnmodifiableBag

java.lang.Object
  |
  +--org.apache.commons.collections.collection.AbstractCollectionDecorator
        |
        +--org.apache.commons.collections.bag.AbstractBagDecorator
              |
              +--org.apache.commons.collections.bag.UnmodifiableBag
All Implemented Interfaces:
Bag, Collection, Unmodifiable

public final class UnmodifiableBag
extends AbstractBagDecorator
implements Unmodifiable

Decorates another Bag to ensure it can't be altered.

Since:
Commons Collections 3.0
Version:
$Revision: 1.5 $ $Date: 2004/01/14 21:43:08 $
Author:
Stephen Colebourne

Fields inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
collection
 
Method Summary
 boolean add(Object object)
          (Violation) Adds one copy the specified object to the Bag.
 boolean add(Object object, int count)
          Adds nCopies copies of the specified object to the Bag.
 boolean addAll(Collection coll)
           
 void clear()
           
static Bag decorate(Bag bag)
          Factory method to create an unmodifiable 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 count)
          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.
 Set uniqueSet()
          Returns a Set of unique elements in the Bag.
 
Methods inherited from class org.apache.commons.collections.bag.AbstractBagDecorator
getBag, getCount
 
Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
contains, containsAll, equals, getCollection, hashCode, isEmpty, 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
containsAll, size
 
Methods inherited from interface java.util.Collection
contains, equals, hashCode, isEmpty, toArray, toArray
 

Method Detail

decorate

public static Bag decorate(Bag bag)
Factory method to create an unmodifiable bag.
Parameters:
bag - the bag to decorate, must not be null
Throws:
IllegalArgumentException - if bag is null

iterator

public Iterator iterator()
Description copied from interface: Bag
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.
Overrides:
iterator in class AbstractCollectionDecorator
Following copied from interface: org.apache.commons.collections.Bag
Returns:
iterator over all elements in the Bag

add

public boolean add(Object object)
Description copied from interface: Bag
(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. A future version of this method will comply by always returning true.

Overrides:
add in class AbstractCollectionDecorator
Following copied from interface: org.apache.commons.collections.Bag
Parameters:
object - the object to add
Returns:
true if the object was not already in the uniqueSet

addAll

public boolean addAll(Collection coll)
Overrides:
addAll in class AbstractCollectionDecorator

clear

public void clear()
Overrides:
clear in class AbstractCollectionDecorator

remove

public boolean remove(Object object)
Description copied from interface: Bag
(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. A future version of this method will comply with the contract by only removing one occurrence of the given object.

Overrides:
remove in class AbstractCollectionDecorator
Following copied from interface: org.apache.commons.collections.Bag
Returns:
true if this call changed the collection

removeAll

public boolean removeAll(Collection coll)
Description copied from interface: Bag
(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. A future version of this method will comply with that contract.

Overrides:
removeAll in class AbstractCollectionDecorator
Following copied from interface: org.apache.commons.collections.Bag
Parameters:
coll - the collection to remove
Returns:
true if this call changed the collection

retainAll

public boolean retainAll(Collection coll)
Description copied from interface: Bag
(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. A future version of this method will comply with that contract.

Overrides:
retainAll in class AbstractCollectionDecorator
Following copied from interface: org.apache.commons.collections.Bag
Parameters:
coll - the collection to retain
Returns:
true if this call changed the collection

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.

Overrides:
add in class AbstractBagDecorator
Following copied from interface: org.apache.commons.collections.Bag
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

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.

Overrides:
remove in class AbstractBagDecorator
Following copied from interface: org.apache.commons.collections.Bag
Parameters:
object - the object to remove
nCopies - 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.

Overrides:
uniqueSet in class AbstractBagDecorator
Following copied from interface: org.apache.commons.collections.Bag
Returns:
the Set of unique Bag elements


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