Package org.apache.commons.collections4.bidimap

Class AbstractBidiMapDecorator<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>, BidiMap<K,​V>, Get<K,​V>, IterableGet<K,​V>, IterableMap<K,​V>, Put<K,​V>
    Direct Known Subclasses:
    AbstractOrderedBidiMapDecorator, UnmodifiableBidiMap
    public abstract class AbstractBidiMapDecorator<K,​V>
extends AbstractMapDecorator<K,​V>
implements BidiMap<K,​V>
    Provides a base decorator that enables additional functionality to be added to a BidiMap 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

    • Constructor Detail

      • AbstractBidiMapDecorator

        protected AbstractBidiMapDecorator​(BidiMap<K,​V> map)
        Constructor that wraps (not copies).
        Parameters:
        map - the map to decorate, must not be null
        Throws:
        NullPointerException - if the collection is null

    • Method Detail

      • mapIterator

        public MapIterator<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>
        Overrides:
        mapIterator in class AbstractIterableMap<K,​V>
        Returns:
        a map iterator

      • getKey

        public K getKey​(Object value)
        Description copied from interface: BidiMap
        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).

        Specified by:
        getKey in interface BidiMap<K,​V>
        Parameters:
        value - the value to find the key for
        Returns:
        the mapped key, or null if not found

      • removeValue

        public K removeValue​(Object value)
        Description copied from interface: BidiMap
        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).

        Specified by:
        removeValue in interface BidiMap<K,​V>
        Parameters:
        value - the value to find the key-value pair for
        Returns:
        the key that was removed, null if nothing removed

      • inverseBidiMap

        public BidiMap<V,​K> inverseBidiMap()
        Description copied from interface: BidiMap
        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.

        Specified by:
        inverseBidiMap in interface BidiMap<K,​V>
        Returns:
        an inverted bidirectional map

      • values

        public Set<V> values()
        Description copied from interface: BidiMap
        Returns a Set view of the values contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.
        Specified by:
        values in interface BidiMap<K,​V>
        Specified by:
        values in interface Get<K,​V>
        Specified by:
        values in interface Map<K,​V>
        Overrides:
        values in class AbstractMapDecorator<K,​V>
        Returns:
        a collection view of the values contained in this map
        See Also:
        Map.values()