Package org.apache.commons.collections.map

Class AbstractLinkedMap

java.lang.Object
java.util.AbstractMap
org.apache.commons.collections.map.AbstractHashedMap
org.apache.commons.collections.map.AbstractLinkedMap
All Implemented Interfaces:
Map, IterableMap, OrderedMap
Direct Known Subclasses:
LinkedMap, LRUMap
@Deprecated(since="2021-04-30") public class AbstractLinkedMap extends AbstractHashedMap implements OrderedMap
Deprecated.
Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
An abstract implementation of a hash-based map that links entries to create an ordered map and which provides numerous points for subclasses to override.

This class implements all the features necessary for a subclass linked hash-based map. Key-value entries are stored in instances of the LinkEntry class which can be overridden and replaced. The iterators can similarly be replaced, without the need to replace the KeySet, EntrySet and Values view classes.

Overridable methods are provided to change the default hashing behaviour, and to change how entries are added to and removed from the map. Hopefully, all you need for unusual subclasses is here.

This implementation maintains order by original insertion, but subclasses may work differently. The OrderedMap interface is implemented to provide access to bidirectional iteration and extra convenience methods.

The orderedMapIterator() method provides direct access to a bidirectional iterator. The iterators from the other views can also be cast to OrderedIterator if required.

All the available iterators can be reset back to the start by casting to ResettableIterator and calling reset().

The implementation is also designed to be subclassed, with lots of useful methods exposed.

Since:
Commons Collections 3.0

  • Method Details

    • containsValue

      public boolean containsValue(Object value)
      Deprecated.
      Checks whether the map contains the specified value.
      Specified by:
      containsValue in interface Map
      Overrides:
      containsValue in class AbstractHashedMap
      Parameters:
      value - the value to search for
      Returns:
      true if the map contains the value

    • clear

      public void clear()
      Deprecated.
      Clears the map, resetting the size to zero and nullifying references to avoid garbage collection issues.
      Specified by:
      clear in interface Map
      Overrides:
      clear in class AbstractHashedMap

    • firstKey

      public Object firstKey()
      Deprecated.
      Gets the first key in the map, which is the most recently inserted.
      Specified by:
      firstKey in interface OrderedMap
      Returns:
      the most recently inserted key

    • lastKey

      public Object lastKey()
      Deprecated.
      Gets the last key in the map, which is the first inserted.
      Specified by:
      lastKey in interface OrderedMap
      Returns:
      the eldest key

    • nextKey

      public Object nextKey(Object key)
      Deprecated.
      Gets the next key in sequence.
      Specified by:
      nextKey in interface OrderedMap
      Parameters:
      key - the key to get after
      Returns:
      the next key

    • previousKey

      public Object previousKey(Object key)
      Deprecated.
      Gets the previous key in sequence.
      Specified by:
      previousKey in interface OrderedMap
      Parameters:
      key - the key to get before
      Returns:
      the previous key

    • mapIterator

      public MapIterator mapIterator()
      Deprecated.
      Gets an iterator over the map. Changes made to the iterator affect this map.

      A MapIterator returns the keys in the map. It also provides convenient methods to get the key and value, and set the value. It avoids the need to create an entrySet/keySet/values object.

      Specified by:
      mapIterator in interface IterableMap
      Overrides:
      mapIterator in class AbstractHashedMap
      Returns:
      the map iterator

    • orderedMapIterator

      public OrderedMapIterator orderedMapIterator()
      Deprecated.
      Gets a bidirectional iterator over the map. Changes made to the iterator affect this map.

      A MapIterator returns the keys in the map. It also provides convenient methods to get the key and value, and set the value. It avoids the need to create an entrySet/keySet/values object.

      Specified by:
      orderedMapIterator in interface OrderedMap
      Returns:
      the map iterator