KeyValueStore Contract — Key-Value State Stores with Range Queries

KeyValueStore (KeyValueStore<K, V>) is the extension of the StateStore contract for key-value state stores that allow for inserting, updating and deleting key-value pairs.

KeyValueStore is also a ReadOnlyKeyValueStore that allows for range queries.

Table 1. KeyValueStore Contract
Method	Description
`delete`	`V delete(K key)` Deletes the value for the non-`null` key from the store (if there was one) and gives the old value or `null` if there was no such key. The key must not be `null` or an `NullPointerException` is thrown.
`put`	`void put(K key, V value)` Inserts or updates the value associated with the key
`putAll`	`void putAll(List<KeyValue<K, V>> entries)`
`putIfAbsent`	`V putIfAbsent(K key, V value)`

Table 2. KeyValueStores (Direct Implementations and Extensions Only)
KeyValueStore	Description
CachingKeyValueStore
ChangeLoggingKeyValueBytesStore
InMemoryKeyValueStore
InMemoryTimestampedKeyValueStoreMarker
KeyValueToTimestampedKeyValueByteStoreAdapter
MemoryLRUCache
MeteredKeyValueStore
RocksDBStore
Segment
TimestampedKeyValueStore

KeyValueStore