Package com.google.common.collect

Interface BiMap<K extends @Nullable Object,​V extends @Nullable Object>

  • All Superinterfaces:
    Map<K,​V>
    All Known Implementing Classes:
    EnumBiMap, EnumHashBiMap, HashBiMap, ImmutableBiMap
    @GwtCompatible
public interface BiMap<K extends @Nullable Object,​V extends @Nullable Object>
extends Map<K,​V>
    A bimap (or "bidirectional map") is a map that preserves the uniqueness of its values as well as that of its keys. This constraint enables bimaps to support an "inverse view", which is another bimap containing the same entries as this bimap but with reversed keys and values.

    See the Guava User Guide article on BiMap.

    Since:
    2.0
    Author:
    Kevin Bourrillion

    • Method Detail

      • put

        @CanIgnoreReturnValue
@CheckForNull
V put​(K key,
      V value)
        Associates the specified value with the specified key in this map (optional operation). If the map previously contained a mapping for the key, the old value is replaced by the specified value. (A map m is said to contain a mapping for a key k if and only if m.containsKey(k) would return true.)
        Specified by:
        put in interface Map<K extends @Nullable Object,​V extends @Nullable Object>
        Parameters:
        key - key with which the specified value is to be associated
        value - value to be associated with the specified key
        Returns:
        the previous value associated with key, or null if there was no mapping for key. (A null return can also indicate that the map previously associated null with key, if the implementation supports null values.)
        Throws:
        IllegalArgumentException - if the given value is already bound to a different key in this bimap. The bimap will remain unmodified in this event. To avoid this exception, call forcePut(K, V) instead.

      • forcePut

        @CanIgnoreReturnValue
@CheckForNull
V forcePut​(K key,
           V value)
        An alternate form of put that silently removes any existing entry with the value value before proceeding with the put(K, V) operation. If the bimap previously contained the provided key-value mapping, this method has no effect.

        Note that a successful call to this method could cause the size of the bimap to increase by one, stay the same, or even decrease by one.

        Warning: If an existing entry with this value is removed, the key for that entry is discarded and not returned.

        Parameters:
        key - the key with which the specified value is to be associated
        value - the value to be associated with the specified key
        Returns:
        the value that was previously associated with the key, or null if there was no previous entry. (If the bimap contains null values, then forcePut, like put, returns null both if the key is absent and if it is present with a null value.)

      • putAll

        void putAll​(Map<? extends K,​? extends V> map)
        Copies all of the mappings from the specified map to this map (optional operation). The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map. The behavior of this operation is undefined if the specified map is modified while the operation is in progress.

        Warning: the results of calling this method may vary depending on the iteration order of map.

        Specified by:
        putAll in interface Map<K extends @Nullable Object,​V extends @Nullable Object>
        Parameters:
        map - mappings to be stored in this map
        Throws:
        IllegalArgumentException - if an attempt to put any entry fails. Note that some map entries may have been added to the bimap before the exception was thrown.

      • values

        Set<V> values()
        Returns a Collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The collection 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.

        Because a bimap has unique values, this method returns a Set, instead of the Collection specified in the Map interface.

        Specified by:
        values in interface Map<K extends @Nullable Object,​V extends @Nullable Object>
        Returns:
        a collection view of the values contained in this map

      • inverse

        BiMap<V,​K> inverse()
        Returns the inverse view of this bimap, which maps each of this bimap's values to its associated key. The two bimaps are backed by the same data; any changes to one will appear in the other.

        Note:There is no guaranteed correspondence between the iteration order of a bimap and that of its inverse.

        Returns:
        the inverse view of this bimap