org.apache.commons.collections
Class BagUtils
java.lang.Object
org.apache.commons.collections.BagUtils
public class BagUtils
extends java.lang.Object
Provides utility methods and decorators for
Bag
and
SortedBag
instances.
$Id: BagUtils.java,v 1.7.2.1 2004/05/22 12:14:01 scolebourne Exp $- Paul Jack
- Stephen Colebourne
predicatedBag
public static Bag predicatedBag(Bag bag,
Predicate predicate)
Returns a predicated bag backed by the given bag. Only objects
that pass the test in the given predicate can be added to the bag.
It is important not to use the original bag after invoking this
method, as it is a backdoor for adding unvalidated objects.
bag
- the bag to predicate, must not be nullpredicate
- the predicate for the bag, must not be null
- a predicated bag backed by the given bag
predicatedSortedBag
public static SortedBag predicatedSortedBag(SortedBag bag,
Predicate predicate)
Returns a predicated sorted bag backed by the given sorted bag.
Only objects that pass the test in the given predicate can be
added to the bag.
It is important not to use the original bag after invoking this
method, as it is a backdoor for adding unvalidated objects.
bag
- the sorted bag to predicate, must not be nullpredicate
- the predicate for the bag, must not be null
- a predicated bag backed by the given bag
synchronizedBag
public static Bag synchronizedBag(Bag bag)
Returns a synchronized (thread-safe) bag backed by the given bag.
In order to guarantee serial access, it is critical that all
access to the backing bag is accomplished through the returned bag.
It is imperative that the user manually synchronize on the returned
bag when iterating over it:
Bag bag = BagUtils.synchronizedBag(new HashBag());
...
synchronized(bag) {
Iterator i = bag.iterator(); // Must be in synchronized block
while (i.hasNext())
foo(i.next());
}
}
Failure to follow this advice may result in non-deterministic
behavior.
bag
- the bag to synchronize, must not be null
- a synchronized bag backed by that bag
synchronizedSortedBag
public static SortedBag synchronizedSortedBag(SortedBag bag)
Returns a synchronized (thread-safe) sorted bag backed by the given
sorted bag.
In order to guarantee serial access, it is critical that all
access to the backing bag is accomplished through the returned bag.
It is imperative that the user manually synchronize on the returned
bag when iterating over it:
SortedBag bag = BagUtils.synchronizedSortedBag(new TreeBag());
...
synchronized(bag) {
Iterator i = bag.iterator(); // Must be in synchronized block
while (i.hasNext())
foo(i.next());
}
}
Failure to follow this advice may result in non-deterministic
behavior.
bag
- the bag to synchronize, must not be null
- a synchronized bag backed by that bag
unmodifiableBag
public static Bag unmodifiableBag(Bag bag)
Returns an unmodifiable view of the given bag. Any modification
attempts to the returned bag will raise an
UnsupportedOperationException
.
bag
- the bag whose unmodifiable view is to be returned, must not be null
- an unmodifiable view of that bag
unmodifiableSortedBag
public static SortedBag unmodifiableSortedBag(SortedBag bag)
Returns an unmodifiable view of the given sorted bag. Any modification
attempts to the returned bag will raise an
UnsupportedOperationException
.
bag
- the bag whose unmodifiable view is to be returned, must not be null
- an unmodifiable view of that bag
Copyright © 2001-2004 Apache Software Foundation. Documenation generated ${TODAY}.