org.apache.commons.collections.map

## Class AbstractOrderedMapDecorator

- java.lang.Object
- - org.apache.commons.collections.map.AbstractMapDecorator
  - - org.apache.commons.collections.map.AbstractOrderedMapDecorator

- All Implemented Interfaces:
    Map, IterableMap, OrderedMap
  Direct Known Subclasses:
    UnmodifiableOrderedMap

      public abstract class AbstractOrderedMapDecorator
      extends AbstractMapDecorator
      implements OrderedMap

  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:
    Commons Collections 3.0
  Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  Author:
    Stephen Colebourne

- - ### Nested Class Summary

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

      `Map.Entry`

  - ### Field Summary

    - ### Fields inherited from class org.apache.commons.collections.map.AbstractMapDecorator

      `map`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `AbstractOrderedMapDecorator()` Constructor only used in deserialization, do not use otherwise.
    `` | `AbstractOrderedMapDecorator(OrderedMap map)` Constructor that wraps (not copies).

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Object` | `firstKey()` Gets the first key currently in this map.
    `protected OrderedMap` | `getOrderedMap()` Gets the map being decorated.
    `Object` | `lastKey()` Gets the last key currently in this map.
    `MapIterator` | `mapIterator()` Obtains a `MapIterator` over the map.
    `Object` | `nextKey(Object key)` Gets the next key after the one specified.
    `OrderedMapIterator` | `orderedMapIterator()` Obtains an `OrderedMapIterator` over the map.
    `Object` | `previousKey(Object key)` Gets the previous key before the one specified.

    - ### Methods inherited from class org.apache.commons.collections.map.AbstractMapDecorator

      `clear, containsKey, containsValue, entrySet, equals, get, getMap, 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 java.util.Map

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

- - ### Constructor Detail

    - #### AbstractOrderedMapDecorator

          protected AbstractOrderedMapDecorator()

      Constructor only used in deserialization, do not use otherwise.
      Since:
        Commons Collections 3.1

    - #### AbstractOrderedMapDecorator

          public AbstractOrderedMapDecorator(OrderedMap map)

      Constructor that wraps (not copies).
      Parameters:
        `map` - the map to decorate, must not be null
      Throws:
        `IllegalArgumentException` - if the collection is null

  - ### Method Detail

    - #### getOrderedMap

          protected OrderedMap getOrderedMap()

      Gets the map being decorated.
      Returns:
        the decorated map

    - #### firstKey

          public Object firstKey()

      Description copied from interface: `OrderedMap`
      Gets the first key currently in this map.
      Specified by:
        `firstKey` in interface `OrderedMap`
      Returns:
        the first key currently in this map

    - #### lastKey

          public Object lastKey()

      Description copied from interface: `OrderedMap`
      Gets the last key currently in this map.
      Specified by:
        `lastKey` in interface `OrderedMap`
      Returns:
        the last key currently in this map

    - #### nextKey

          public Object nextKey(Object key)

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

    - #### previousKey

          public Object previousKey(Object key)

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

    - #### mapIterator

          public MapIterator mapIterator()

      Description copied from interface: `IterableMap`
      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 cast to Map Entry objects.

           IterableMap map = new HashedMap();
           MapIterator it = map.mapIterator();
           while (it.hasNext()) {
             Object key = it.next();
             Object value = it.getValue();
             it.setValue("newValue");
           }

      Specified by:
        `mapIterator` in interface `IterableMap`
      Returns:
        a map iterator

    - #### orderedMapIterator

          public OrderedMapIterator orderedMapIterator()

      Description copied from interface: `OrderedMap`
      Obtains an `OrderedMapIterator` over the map.

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

           BidiMap map = new TreeBidiMap();
           MapIterator it = map.mapIterator();
           while (it.hasNext()) {
             Object key = it.next();
             Object value = it.getValue();
             it.setValue("newValue");
             Object previousKey = it.previous();
           }

      Specified by:
        `orderedMapIterator` in interface `OrderedMap`
      Returns:
        a map iterator

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