kafka-streams-internals-StateManager.adoc

StateManager Contract — State Store Managers

StateManager is the contract of state store managers that manage state stores and are checkpointable.

Table 1. StateManager Contract

Method	Description
baseDir	File baseDir() Base directory Used exclusively when AbstractProcessorContext is requested for the state directory
close	void close( Map<TopicPartition, Long> offsets) Closes a state manager Used when: AbstractTask is requested to close the state manager GlobalStateUpdateTask is requested to close the state manager
flush	void flush() Flushes all state stores registered (in the state manager) Used when: AbstractTask and GlobalStateUpdateTask are requested to flush state stores StandbyTask is requested to flush and checkpoint state stores
getGlobalStore	StateStore getGlobalStore( String name) Accessing the global state store by name Used when: GlobalProcessorContextImpl and ProcessorContextImpl are requested to get the global state store by name GlobalStateManagerImpl is requested to get state store by name
getStore	StateStore getStore( String name) Accessing the state store by name Used when AbstractTask and ProcessorContextImpl are requested to get the state store by name
register	void register( StateStore store, StateRestoreCallback stateRestoreCallback) Registers a state store (with an associated StateRestoreCallback) Used exclusively when AbstractProcessorContext is requested to register a state store
reinitializeStateStoresForPartitions	void reinitializeStateStoresForPartitions( Collection<TopicPartition> partitions, InternalProcessorContext processorContext) Used when: AbstractTask is requested to reinitializeStateStoresForPartitions GlobalStateManagerImpl is requested to restoreState

Table 2. StateManagers (Direct Extensions)

StateManager	Description
AbstractStateManager
GlobalStateManager