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.
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.
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

AbstractBag	This class provides a skeletal implementation of the Bag interface to minimize the effort required for target implementations.
ArrayIterator	Implements an Iterator over an array of objects.
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.
BeanMap	An implementation of Map for JavaBeans which uses introspection to get and put properties in the bean.
BeanMap.MyMapEntry
BinaryHeap	Binary heap implementation of PriorityQueue.
CollectionUtils	A set of Collection related utility methods.
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	Adapter to make Enumeration instances appear to be Iterator instances.
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	A Proxy Iterator which takes a Predicate instance to filter out objects from an underlying Iterator instance.
FilterListIterator	A proxy ListIterator which takes a Predicate instance to filter out objects from an underlying ListIterator instance.
HashBag	An implementation of Bag that is backed by a HashMap.
IteratorEnumeration	Adapter to make an Iterator instance appear to be an Enumeration 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	see MultiMap for details of an important semantic difference between this and a typical HashMap
ProxyIterator	A Proxy Iterator which delegates its methods to a proxy instance.
ProxyListIterator	A proxy ListIterator which delegates its methods to a proxy instance.
ProxyMap	This Map wraps another Map implementation, using the wrapped instance for its default implementation.
SequencedHashMap	A map of objects whose mapping entries are sequenced based on the order in which they were added.
SingletonIterator	SingletonIterator is an Iterator over a single object instance.
SoftRefHashMap	HashMap with SoftReference links to values which allows the values of the Map to be garbage collected by the JVM if it becomes low on memory.
StringStack	This class implements a stack for String objects.
SynchronizedPriorityQueue	A thread safe version of the PriorityQueue.
TransformIterator	A Proxy Iterator which uses a Transformer instance to transform the contents of the Iterator into some other form
TreeBag	An implementation of Bag that is backed by a TreeMap.

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 DefaultMapEntry ExtendedProperties FastHashMap FastTreeMap LRUMap SoftRefHashMap DoubleOrderedMap	Special-purpose implementations of the Map interface.
Stack and Queue Implementations	ArrayStack BinaryHeap PriorityQueue SynchronizedPriorityQueue	Special-purpose implementations of the Stack interface, as well as similar PriorityQueue interface.
Bag Interface and Implementations	Bag HashBag SortedBag TreeBag	New collections interface that keeps a count of its members.
Adapters	ArrayEnumeration ArrayIterator EnumerationIterator IteratorEnumeration	Access Java1-style containers as though they were Java2-style Collections and vice-versa.
Utilities	Closure CollectionUtils MapUtils	Manipulate collection objects, determine set theoretic properties, ensure type-safety, etc.
Transformation Tools	FilterIterator Predicate ProxyIterator Transformer TransformIterator	Create views or functors on a collection. If your collection represents X, these allow you to define and look at f(X).