Package org.apache.commons.collections

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	Enumeration wrapper for array.
ArrayIterator	Implements an java.util.Iterator over an array of objects.
ArrayStack	An implementation of the java.util.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.
BeanMap.MyMapEntry	Map entry used by BeanMap.
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.
BufferOverflowException	The BufferOverflowException is used when the buffer's capacity has been exceeded.
BufferUnderflowException	The BufferUnderflowException is used when the buffer is already empty
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.
CursorableLinkedList.Cursor
DefaultMapBag	This class provides a skeletal implementation of the Bag interface to minimize the effort required for target implementations.
DefaultMapEntry	A default implementation of java.util.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
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	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.
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	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.
StaticBucketMap	A StaticBucketMap is an efficient, thread-safe implementation of java.util.Map that performs well in in a highly thread-contentious environment.
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.
UnboundedFifoBuffer	UnboundedFifoBuffer is a very efficient buffer implementation.