org.apache.storm.state

## Interface KeyValueState<K,V>

- All Superinterfaces:
    Iterable<Map.Entry<K,V>>, State
  All Known Implementing Classes:
    HBaseKeyValueState, InMemoryKeyValueState, RedisKeyValueState

      public interface KeyValueState<K,V>
      extends State, Iterable<Map.Entry<K,V>>

  A state that supports key-value mappings.

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `V` | `delete(K key)` Deletes the value mapped to the key, if there is any.
    `V` | `get(K key)` Returns the value mapped to the key.
    `V` | `get(K key, V defaultValue)` Returns the value mapped to the key or defaultValue if no mapping is found.
    `void` | `put(K key, V value)` Maps the value with the key.

    - ### Methods inherited from interface org.apache.storm.state.State

      `commit, commit, prepareCommit, rollback`

    - ### Methods inherited from interface java.lang.Iterable

      `forEach, iterator, spliterator`

- - ### Method Detail

    - #### put

          void put(K key,
                   V value)

      Maps the value with the key.

      Parameters:
        `key` - the key
        `value` - the value

    - #### get

          V get(K key)

      Returns the value mapped to the key.

      Parameters:
        `key` - the key
      Returns:
        the value or null if no mapping is found

    - #### get

          V get(K key,
                V defaultValue)

      Returns the value mapped to the key or defaultValue if no mapping is found.

      Parameters:
        `key` - the key
        `defaultValue` - the value to return if no mapping is found
      Returns:
        the value or defaultValue if no mapping is found

    - #### delete

          V delete(K key)

      Deletes the value mapped to the key, if there is any.

      Parameters:
        `key` - the key

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