Interface Multimap<K,V>

Type Parameters:
K - the type of keys maintained by this multimap
V - the type of values that can be associated with the keys
All Superinterfaces:
ImmutableMultimap<K,V>
All Known Implementing Classes:
ArtifactMultimap, LinkedSetMultimap, ListMultimap, SetMultimap, TreeMultimap

public interface Multimap<K,V> extends ImmutableMultimap<K,V>
The Multimap interface defines a collection that maps keys to values, similar to Map, but in which each key may be associated with multiple values. Implementations of this interface manage collections of keys and values where the values are typically stored in a collection under a single key.

This interface provides a unified approach to handling multiple values associated with a single key which is a common requirement in many applications. The implementations can vary in the type of collections they use to store the values associated with the keys, such as lists, sets, etc.

Since:
10.0
  • Method Summary

    Modifier and Type
    Method
    Description
    Returns a view of the mappings contained in this multimap as a map from each key to its corresponding values.
    boolean
    Returns true if this multimap contains one or more keys to the specified value.
    Creates a deep copy of this multimap.
    Returns a collection view of all key-value pairs contained in this multimap.
    get(K key)
    Retrieves the collection of values associated with the specified key in this multimap.
    Creates an inverse view of this multimap.
    boolean
    Returns true if this multimap contains no key-value mappings.
    Returns the set of keys contained in this multimap.
    void
    put(K key, V value)
    Associates the specified value with the specified key in this multimap.
    void
    putAll(K key, Collection<? extends V> values)
    Associates all of the values in the specified collection with the specified key in this multimap.
    void
    remove(K key, V value)
    Removes a single instance of the specified value from the multimap, if it is present.
    void
    removeAll(K key)
    Removes all the values associated with the specified key in this multimap.
    int
    Returns the total number of key-value pairs in the multimap.
    Returns a collection view of all values associated with keys in this multimap.
  • Method Details

    • put

      void put(K key, V value)
      Associates the specified value with the specified key in this multimap. If the multimap previously contained a mapping for the key, the new value is added to the collection of values mapped to that key.
      Parameters:
      key - key with which the specified value is to be associated
      value - value to be associated with the specified key
    • putAll

      void putAll(K key, Collection<? extends V> values)
      Associates all of the values in the specified collection with the specified key in this multimap. If the multimap previously contained mappings for the key, the new values are added to the collection of values mapped to that key.
      Parameters:
      key - key with which the specified values are to be associated
      values - collection of values to be associated with the specified key
    • get

      Collection<V> get(K key)
      Retrieves the collection of values associated with the specified key in this multimap.
      Specified by:
      get in interface ImmutableMultimap<K,V>
      Parameters:
      key - the key whose associated values are to be returned
      Returns:
      the collection of values associated with the specified key, or an empty collection if no values are associated with the key
    • remove

      void remove(K key, V value)
      Removes a single instance of the specified value from the multimap, if it is present.
      Parameters:
      key - key with which the specified value is associated
      value - value to be removed from the collection of values for the specified key
    • removeAll

      void removeAll(K key)
      Removes all the values associated with the specified key in this multimap.
      Parameters:
      key - key whose associated values are to be removed
    • keySet

      Set<K> keySet()
      Returns the set of keys contained in this multimap.
      Specified by:
      keySet in interface ImmutableMultimap<K,V>
      Returns:
      the set of keys contained in this multimap
    • containsKey

      boolean containsKey(K key)
      Returns true if this multimap contains one or more keys to the specified value.
      Specified by:
      containsKey in interface ImmutableMultimap<K,V>
      Parameters:
      key - key whose presence in this multimap is to be tested
      Returns:
      true if this multimap contains a mapping for the specified key
    • values

      Collection<V> values()
      Returns a collection view of all values associated with keys in this multimap.
      Specified by:
      values in interface ImmutableMultimap<K,V>
      Returns:
      a collection view of all values contained in this multimap
    • isEmpty

      boolean isEmpty()
      Returns true if this multimap contains no key-value mappings.
      Specified by:
      isEmpty in interface ImmutableMultimap<K,V>
      Returns:
      true if this multimap contains no key-value mappings
    • asMap

      Map<K,Collection<V>> asMap()
      Returns a view of the mappings contained in this multimap as a map from each key to its corresponding values.
      Specified by:
      asMap in interface ImmutableMultimap<K,V>
      Returns:
      a map view of the mappings contained in this multimap
    • entries

      Collection<Map.Entry<K,V>> entries()
      Returns a collection view of all key-value pairs contained in this multimap. Each key-value pair is represented as a Map.Entry. If the multimap allows duplicate values, a separate Map.Entry will be included for each duplicate value.
      Specified by:
      entries in interface ImmutableMultimap<K,V>
      Returns:
      a collection view of all key-value pairs contained in this multimap
    • size

      int size()
      Returns the total number of key-value pairs in the multimap.
      Specified by:
      size in interface ImmutableMultimap<K,V>
      Returns:
      the total number of key-value pairs
    • copy

      Multimap<K,V> copy()
      Creates a deep copy of this multimap.
      Specified by:
      copy in interface ImmutableMultimap<K,V>
      Returns:
      a new multimap instance containing the same key-value mappings as this multimap
    • inverse

      Multimap<V,K> inverse()
      Creates an inverse view of this multimap. In the inverse multimap, each value in the original multimap becomes a key in the new multimap, and each key in the original becomes part of the set of values associated with the new key. The inverse multimap is also immutable.
      Specified by:
      inverse in interface ImmutableMultimap<K,V>
      Returns:
      a new Multimap instance where the roles of keys and values are swapped