Package org.apache.commons.collections

Java Collections Framework extensions.

See:
Description

Interface Summary

Bag	A Collection that counts the number of times an object appears in the collection.
Buffer	A Buffer is a collection that allows objects to be removed in some well-defined order.
Closure	An interface to represent some Closure, a block of code which is executed from inside some block, function or iteration which operates on an input object.
Factory	Factory A simple interface that describes the most basic means of having the ability to create an object.
MultiMap	This is simply a Map with slightly different semantics.
Predicate	Performs some predicate which returns true or false based on the input object.
PriorityQueue	Interface for priority queues.
SortedBag	A type of Bag that maintains order among its unique representative members.
Transformer	An object capable of transforming an input object into some output object.

Class Summary

ArrayEnumeration	Deprecated. This class has significant overlap with ArrayIterator, and Collections focuses mainly on Java2-style collections.
ArrayIterator	Deprecated. this class has been moved to the iterators subpackage
ArrayStack	An implementation of the Stack API that is based on an ArrayList instead of a Vector, so it is not synchronized to protect against multi-threaded access.
BagUtils	Provides utility methods and decorators for Bag and SortedBag instances.
BeanMap	An implementation of Map for JavaBeans which uses introspection to get and put properties in the bean.
BinaryHeap	Binary heap implementation of PriorityQueue and Buffer.
BoundedFifoBuffer	The BoundedFifoBuffer is a very efficient implementation of Buffer that does not alter the size of the buffer at runtime.
BufferUtils	Contains static utility methods for operating on Buffer objects.
CollectionUtils	A set of Collection related utility methods.
ComparatorUtils	Provides convenient static utility methods for Comparator objects.
CursorableLinkedList	A doubly-linked list implementation of the List interface, supporting a ListIterator that allows concurrent modifications to the underlying list.
DefaultMapBag	This class provides a skeletal implementation of the Bag interface to minimize the effort required for target implementations.
DefaultMapEntry	A default implementation of Map.Entry
DoubleOrderedMap	Red-Black tree-based implementation of Map.
EnumerationIterator	Deprecated. this class has been moved to the iterators subpackage
ExtendedProperties	This class extends normal Java properties by adding the possibility to use the same key many times concatenating the value strings instead of overwriting them.
FastArrayList	A customized implementation of java.util.ArrayList designed to operate in a multithreaded environment where the large majority of method calls are read-only, instead of structural changes.
FastHashMap	A customized implementation of java.util.HashMap designed to operate in a multithreaded environment where the large majority of method calls are read-only, instead of structural changes.
FastTreeMap	A customized implementation of java.util.TreeMap designed to operate in a multithreaded environment where the large majority of method calls are read-only, instead of structural changes.
FilterIterator	Deprecated. this class has been moved to the iterators subpackage
FilterListIterator	Deprecated. this class has been moved to the iterators subpackage
HashBag	An implementation of Bag that is backed by a HashMap.
IteratorEnumeration	Deprecated. this class has been moved to the iterators subpackage
IteratorUtils	Provides static utility methods and decorators for Iterator instances.
ListUtils	Contains static utility methods and decorators for List instances.
LRUMap	An implementation of a Map which has a maximum size and uses a Least Recently Used algorithm to remove items from the Map when the maximum size is reached and new items are added.
MapUtils	A helper class for using Map instances.
MultiHashMap	MultiHashMap is the default implementation of the MultiMap interface.
ProxyIterator	Deprecated. this class has been moved to the iterators subpackage
ProxyListIterator	Deprecated. this class has been moved to the iterators subpackage
ProxyMap	This Map wraps another Map implementation, using the wrapped instance for its default implementation.
ReferenceMap	Hashtable-based Map implementation that allows mappings to be removed by the garbage collector.
SequencedHashMap	A map of objects whose mapping entries are sequenced based on the order in which they were added.
SetUtils	Provides static utility methods and decorators for Set and SortedSet instances.
SingletonIterator	Deprecated. this class has been moved to the iterators subpackage
SoftRefHashMap	Deprecated. This class is all kinds of wonky; use ReferenceMap instead.
StaticBucketMap	A StaticBucketMap is an efficient, thread-safe implementation of java.util.Map that performs well in in a highly thread-contentious environment.
StringStack	Deprecated. This class is not a Stack, it is a String utility.
SynchronizedPriorityQueue	A thread safe version of the PriorityQueue.
TransformIterator	Deprecated. this class has been moved to the iterators subpackage
TreeBag	An implementation of Bag that is backed by a TreeMap.
UnboundedFifoBuffer	UnboundedFifoBuffer is a very efficient buffer implementation.

Exception Summary

BufferOverflowException	The BufferOverflowException is used when the buffer's capacity has been exceeded.
BufferUnderflowException	The BufferUnderflowException is used when the buffer is already empty

Package org.apache.commons.collections Description

Java Collections Framework extensions.

See also the java.util package.

Category	Classes	Comments
List Implementations	CursorableLinkedList FastArrayList	Special-purpose implementations of the List interface.
Map Implementations	BeanMap DoubleOrderedMap ExtendedProperties FastHashMap FastTreeMap LRUMap MultiHashMap ProxyMap ReferenceMap SequencedHashMap SoftRefHashMap StaticBucketMap	Special-purpose implementations of the Map interface and associated classes.
Buffer Interface and Implementations	ArrayStack BinaryHeap BoundedFifoBuffer Buffer PriorityQueue SynchronizedPriorityQueue UnboundedFifoBuffer	New collection interface that specifies a removal order for the collection, used to implement queues and queue-like things.
Bag Interface and Implementations	Bag DefaultMapBag HashBag SortedBag TreeBag	New collections interface that keeps a count of its members.
Utilities	BagUtils BufferUtils CollectionUtils ComparatorUtils ListUtils MapUtils SetUtils	Manipulate collection objects, determine set theoretic properties, ensure type-safety, provide decorators, etc.
Functor Interfaces	Factory Predicate Closure Transformer	Create views or functors on a collection. If your collection represents X, these allow you to define and look at f(X).
Miscellaneous	StringStack DefaultMapEntry	A stack of strings; and the trivial implementation of Map.Entry.