org.apache.commons.collections4
Interface OrderedMap<K,V>

Type Parameters:

K - the type of the keys in the map

V - the type of the values in the map

All Superinterfaces:

Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, Map<K,V>, Put<K,V>

All Known Subinterfaces:

IterableSortedMap<K,V>, OrderedBidiMap<K,V>, SortedBidiMap<K,V>, Trie<K,V>

All Known Implementing Classes:

AbstractBitwiseTrie, AbstractLinkedMap, AbstractOrderedBidiMapDecorator, AbstractOrderedMapDecorator, AbstractSortedBidiMapDecorator, AbstractSortedMapDecorator, DualTreeBidiMap, DualTreeBidiMap.ViewMap, FixedSizeSortedMap, LinkedMap, ListOrderedMap, LRUMap, PatriciaTrie, SingletonMap, TreeBidiMap, UnmodifiableOrderedBidiMap, UnmodifiableOrderedMap, UnmodifiableSortedBidiMap, UnmodifiableSortedMap, UnmodifiableTrie

public interface OrderedMap<K,V>
extends IterableMap<K,V>

Defines a map that maintains order and allows both forward and backward iteration through that order.

Since:

3.0

Version:

$Id: OrderedMap.java 1477779 2013-04-30 18:55:24Z tn $

mapIterator

OrderedMapIterator<K,V> mapIterator()

Obtains an OrderedMapIterator over the map.

A ordered map iterator is an efficient way of iterating over maps in both directions.

Specified by:

mapIterator in interface IterableGet<K,V>

Returns:

a map iterator

firstKey

K firstKey()

Gets the first key currently in this map.

Returns:

the first key currently in this map

Throws:

NoSuchElementException - if this map is empty

lastKey

K lastKey()

Gets the last key currently in this map.

Returns:

the last key currently in this map

Throws:

NoSuchElementException - if this map is empty

nextKey

K nextKey(K key)

Gets the next key after the one specified.

Parameters:

key - the key to search for next from

Returns:

the next key, null if no match or at end

previousKey

K previousKey(K key)

Gets the previous key before the one specified.

Parameters:

key - the key to search for previous from

Returns:

the previous key, null if no match or at start