OrderedMap (Apache Commons Collections 4.2 API)

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

Nested Class Summary
- Nested classes/interfaces inherited from interface java.util.Map
  Map.Entry<K extends Object,V extends Object>

Method Summary

All Methods Instance Methods Abstract Methods
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 Detail
  - 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