Package 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, AbstractPatriciaTrie, 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

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Method Summary

Modifier and Type	Method	Description
K	firstKey()	Gets the first key currently in this map.
K	lastKey()	Gets the last key currently in this map.
OrderedMapIterator<K,V>	mapIterator()	Obtains an OrderedMapIterator over the map.
K	nextKey(K key)	Gets the next key after the one specified.
K	previousKey(K key)	Gets the previous key before the one specified.

Methods inherited from interface org.apache.commons.collections4.Get

containsKey, containsValue, entrySet, get, isEmpty, keySet, remove, size, values

Methods inherited from interface java.util.Map

clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values

Methods inherited from interface org.apache.commons.collections4.Put

clear, put, putAll

Method Details

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

mapIterator

OrderedMapIterator<K,V> mapIterator()

Obtains an OrderedMapIterator over the map.

An 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

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