Package org.apache.commons.collections

Interface BidiMap

All Superinterfaces:
IterableMap, Map
All Known Subinterfaces:
OrderedBidiMap, SortedBidiMap
All Known Implementing Classes:
AbstractBidiMapDecorator, AbstractDualBidiMap, AbstractOrderedBidiMapDecorator, AbstractSortedBidiMapDecorator, DualHashBidiMap, DualTreeBidiMap, TreeBidiMap, UnmodifiableBidiMap, UnmodifiableOrderedBidiMap, UnmodifiableSortedBidiMap
@Deprecated(since="2021-04-30") public interface BidiMap extends IterableMap
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.
Defines a map that allows bidirectional lookup between key and values.

This extended Map represents a mapping where a key may lookup a value and a value may lookup a key with equal ease. This interface extends Map and so may be used anywhere a map is required. The interface provides an inverse map view, enabling full access to both directions of the BidiMap.

Implementations should allow a value to be looked up from a key and a key to be looked up from a value with equal performance.

This map enforces the restriction that there is a 1:1 relation between keys and values, meaning that multiple keys cannot map to the same value. This is required so that "inverting" the map results in a map without duplicate keys. See the put(java.lang.Object, java.lang.Object) method description for more information.

Since:
Commons Collections 3.0

  • Method Details

    • mapIterator

      MapIterator mapIterator()
      Deprecated.
      Obtains a MapIterator over the map.

      A map iterator is an efficient way of iterating over maps. It does not require that the map is stored using Map Entry objects which can increase performance. 

       BidiMap map = new DualHashBidiMap();
 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

    • put

      Object put(Object key, Object value)
      Deprecated.
      Puts the key-value pair into the map, replacing any previous pair.

      When adding a key-value pair, the value may already exist in the map against a different key. That mapping is removed, to ensure that the value only occurs once in the inverse map. 

        BidiMap map1 = new DualHashBidiMap();
  map.put("A","B");  // contains A mapped to B, as per Map
  map.put("A","C");  // contains A mapped to C, as per Map

  BidiMap map2 = new DualHashBidiMap();
  map.put("A","B");  // contains A mapped to B, as per Map
  map.put("C","B");  // contains C mapped to B, key A is removed
      Specified by:
      put in interface Map
      Parameters:
      key - the key to store
      value - the value to store
      Returns:
      the previous value mapped to this key
      Throws:
      UnsupportedOperationException - if the put method is not supported
      ClassCastException - (optional) if the map limits the type of the value and the specified value is inappropriate
      IllegalArgumentException - (optional) if the map limits the values in some way and the value was invalid
      NullPointerException - (optional) if the map limits the values to non-null and null was specified

    • getKey

      Object getKey(Object value)
      Deprecated.
      Gets the key that is currently mapped to the specified value.

      If the value is not contained in the map, null is returned.

      Implementations should seek to make this method perform equally as well as get(Object).

      Parameters:
      value - the value to find the key for
      Returns:
      the mapped key, or null if not found
      Throws:
      ClassCastException - (optional) if the map limits the type of the value and the specified value is inappropriate
      NullPointerException - (optional) if the map limits the values to non-null and null was specified

    • removeValue

      Object removeValue(Object value)
      Deprecated.
      Removes the key-value pair that is currently mapped to the specified value (optional operation).

      If the value is not contained in the map, null is returned.

      Implementations should seek to make this method perform equally as well as remove(Object).

      Parameters:
      value - the value to find the key-value pair for
      Returns:
      the key that was removed, null if nothing removed
      Throws:
      ClassCastException - (optional) if the map limits the type of the value and the specified value is inappropriate
      NullPointerException - (optional) if the map limits the values to non-null and null was specified
      UnsupportedOperationException - if this method is not supported by the implementation

    • inverseBidiMap

      BidiMap inverseBidiMap()
      Deprecated.
      Gets a view of this map where the keys and values are reversed.

      Changes to one map will be visible in the other and vice versa. This enables both directions of the map to be accessed as a Map.

      Implementations should seek to avoid creating a new object every time this method is called. See AbstractMap.values() etc. Calling this method on the inverse map should return the original.

      Returns:
      an inverted bidirectional map