# Class AbstractOrderedMapDecorator<K,V>

java.lang.Object
org.apache.commons.collections4.map.AbstractIterableMap<K,V>
org.apache.commons.collections4.map.AbstractMapDecorator<K,V>
org.apache.commons.collections4.map.AbstractOrderedMapDecorator<K,V>

Type Parameters:
  `K` - the type of the keys in this map
  `V` - the type of the values in this map

All Implemented Interfaces:
  `Map<K,V>`, `Get<K,V>`, `IterableGet<K,V>`, `IterableMap<K,V>`, `OrderedMap<K,V>`, `Put<K,V>`

Direct Known Subclasses:
  `UnmodifiableOrderedMap`

public abstract class AbstractOrderedMapDecorator<K,V> extends AbstractMapDecorator<K,V> implements OrderedMap<K,V>
Provides a base decorator that enables additional functionality to be added to an OrderedMap via decoration.

Methods are forwarded directly to the decorated map.

This implementation does not perform any special processing with the map views. Instead it simply returns the set/collection from the wrapped map. This may be undesirable, for example if you are trying to write a validating implementation it would provide a loophole around the validation. But, you might want that loophole, so this class is kept simple.

Since:
  3.0

- ## Nested Class Summary

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

  `Map.Entry<K,V>`

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `AbstractOrderedMapDecorator()`
  Constructor only used in deserialization, do not use otherwise.
  ``
  `AbstractOrderedMapDecorator(OrderedMap<K,V> map)`
  Constructor that wraps (not copies).

- ## Method Summary

  Modifier and Type
  Method
  Description
  `protected OrderedMap<K,V>`
  `decorated()`
  Gets the map being decorated.
  `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 a `MapIterator` 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 class org.apache.commons.collections4.map.AbstractMapDecorator

  `clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, toString, values`

  ### Methods inherited from class java.lang.Object

  `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

  ### 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`

- ## Constructor Details

  - ### AbstractOrderedMapDecorator

    protected AbstractOrderedMapDecorator()
    Constructor only used in deserialization, do not use otherwise.
    Since:
      3.1

  - ### AbstractOrderedMapDecorator

    public AbstractOrderedMapDecorator(OrderedMap<K,V> map)
    Constructor that wraps (not copies).
    Parameters:
      `map` - the map to decorate, must not be null
    Throws:
      `NullPointerException` - if the map is null

- ## Method Details

  - ### decorated

    protected OrderedMap<K,V> decorated()
    Gets the map being decorated.
    Overrides:
      `decorated` in class `AbstractMapDecorator<K,V>`
    Returns:
      the decorated map

  - ### firstKey

    public K firstKey()
    Description copied from interface: `OrderedMap`
    Gets the first key currently in this map.
    Specified by:
      `firstKey` in interface `OrderedMap<K,V>`
    Returns:
      the first key currently in this map

  - ### lastKey

    public K lastKey()
    Description copied from interface: `OrderedMap`
    Gets the last key currently in this map.
    Specified by:
      `lastKey` in interface `OrderedMap<K,V>`
    Returns:
      the last key currently in this map

  - ### mapIterator

    public OrderedMapIterator<K,V> mapIterator()
    Description copied from class: `AbstractIterableMap`
    Obtains a `MapIterator` over the map.

    A map iterator is an efficient way of iterating over maps. There is no need to access the entry set or use Map Entry objects.

         IterableMap<String,Integer> map = new HashedMap<String,Integer>();
         MapIterator<String,Integer> it = map.mapIterator();
         while (it.hasNext()) {
           String key = it.next();
           Integer value = it.getValue();
           it.setValue(value + 1);
         }

    Specified by:
      `mapIterator` in interface `IterableGet<K,V>`
    Specified by:
      `mapIterator` in interface `OrderedMap<K,V>`
    Overrides:
      `mapIterator` in class `AbstractIterableMap<K,V>`
    Returns:
      a map iterator

  - ### nextKey

    public K nextKey(K key)
    Description copied from interface: `OrderedMap`
    Gets the next key after the one specified.
    Specified by:
      `nextKey` in interface `OrderedMap<K,V>`
    Parameters:
      `key` - the key to search for next from
    Returns:
      the next key, null if no match or at end

  - ### previousKey

    public K previousKey(K key)
    Description copied from interface: `OrderedMap`
    Gets the previous key before the one specified.
    Specified by:
      `previousKey` in interface `OrderedMap<K,V>`
    Parameters:
      `key` - the key to search for previous from
    Returns:
      the previous key, null if no match or at start