org.apache.storm.state

Interface KeyValueState<K,V>

All Superinterfaces:

java.lang.Iterable<java.util.Map.Entry<K,V>>, State

All Known Implementing Classes:

InMemoryKeyValueState

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

A state that supports key-value mappings.

Method Summary

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