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:

java.io.Serializable, java.lang.Iterable, java.util.Collection, Bag, Unmodifiable

public final class UnmodifiableBag
extends AbstractBagDecorator
implements Unmodifiable, java.io.Serializable

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

This class is Serializable from Commons Collections 3.1.

Since:

Commons Collections 3.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne

See Also:

Serialized Form

Field Summary

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

collection

Method Summary

boolean	add(java.lang.Object object) (Violation) Adds one copy the specified object to the Bag.
boolean	add(java.lang.Object object, int count) Adds nCopies copies of the specified object to the Bag.
boolean	addAll(java.util.Collection coll)
void	clear()
static Bag	decorate(Bag bag) Factory method to create an unmodifiable bag.
java.util.Iterator	iterator() Returns an Iterator over the entire set of members, including copies due to cardinality.
boolean	remove(java.lang.Object object) (Violation) Removes all occurrences of the given object from the bag.
boolean	remove(java.lang.Object object, int count) Removes nCopies copies of the specified object from the Bag.
boolean	removeAll(java.util.Collection coll) (Violation) Remove all elements represented in the given collection, respecting cardinality.
boolean	retainAll(java.util.Collection coll) (Violation) Remove any members of the bag that are not in the given collection, respecting cardinality.
java.util.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.

If the bag passed in is already unmodifiable, it is returned.

Parameters:

bag - the bag to decorate, must not be null

Returns:

an unmodifiable Bag

Throws:

java.lang.IllegalArgumentException - if bag is null

iterator

public java.util.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.

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Specified by:

iterator in interface Bag

Overrides:

iterator in class AbstractCollectionDecorator

Returns:

iterator over all elements in the Bag

add

public boolean add(java.lang.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.

Specified by:

add in interface java.util.Collection

Specified by:

add in interface Bag

Overrides:

add in class AbstractCollectionDecorator

Parameters:

object - the object to add

Returns:

true if the object was not already in the uniqueSet

addAll

public boolean addAll(java.util.Collection coll)

Specified by:

addAll in interface java.util.Collection

Overrides:

addAll in class AbstractCollectionDecorator

clear

public void clear()

Specified by:

clear in interface java.util.Collection

Overrides:

clear in class AbstractCollectionDecorator

remove

public boolean remove(java.lang.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.

Specified by:

remove in interface java.util.Collection

Specified by:

remove in interface Bag

Overrides:

remove in class AbstractCollectionDecorator

Returns:

true if this call changed the collection

removeAll

public boolean removeAll(java.util.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.

Specified by:

removeAll in interface java.util.Collection

Specified by:

removeAll in interface Bag

Overrides:

removeAll in class AbstractCollectionDecorator

Parameters:

coll - the collection to remove

Returns:

true if this call changed the collection

retainAll

public boolean retainAll(java.util.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.

Specified by:

retainAll in interface java.util.Collection

Specified by:

retainAll in interface Bag

Overrides:

retainAll in class AbstractCollectionDecorator

Parameters:

coll - the collection to retain

Returns:

true if this call changed the collection

add

public boolean add(java.lang.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

Overrides:

add in class AbstractBagDecorator

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(java.lang.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

Overrides:

remove in class AbstractBagDecorator

Parameters:

object - the object to remove

count - the number of copies to remove

Returns:

true if this call changed the collection

uniqueSet

public java.util.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

Overrides:

uniqueSet in class AbstractBagDecorator

Returns:

the Set of unique Bag elements