org.springframework.util

## Interface MultiValueMap<K,V>

- All Superinterfaces:
    Map<K,List<V>>
  All Known Implementing Classes:
    HttpHeaders, LinkedMultiValueMap

      public interface MultiValueMap<K,V>
      extends Map<K,List<V>>

  Extension of the `Map` interface that stores multiple values.
  Since:
    3.0
  Author:
    Arjen Poutsma

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from interface java.util.Map

      `Map.Entry<K,V>`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `add(K key, V value)` Add the given single value to the current list of values for the given key.
    `V` | `getFirst(K key)` Return the first value for the given key.
    `void` | `set(K key, V value)` Set the given single value under the given key.
    `void` | `setAll(Map<K,V> values)` Set the given values under.
    `Map<K,V>` | `toSingleValueMap()` Returns the first values contained in this `MultiValueMap`.

    - ### Methods inherited from interface java.util.Map

      `clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, values`

- - ### Method Detail

    - #### getFirst

          V getFirst(K key)

      Return the first value for the given key.
      Parameters:
        `key` - the key
      Returns:
        the first value for the specified key, or `null`

    - #### add

          void add(K key,
                 V value)

      Add the given single value to the current list of values for the given key.
      Parameters:
        `key` - the key
        `value` - the value to be added

    - #### set

          void set(K key,
                 V value)

      Set the given single value under the given key.
      Parameters:
        `key` - the key
        `value` - the value to set

    - #### setAll

          void setAll(Map<K,V> values)

      Set the given values under.
      Parameters:
        `values` - the values.

    - #### toSingleValueMap

          Map<K,V> toSingleValueMap()

      Returns the first values contained in this `MultiValueMap`.
      Returns:
        a single value representation of this map