Interface RingbufferStore<T>

Type Parameters:

T - ringbuffer item type

public interface RingbufferStore<T>

Service Provider Interface (SPI) for backing a DistributedRingbuffer with an external persistent store.

Implementations are expected to be thread-safe. LoomCache invokes store callbacks from ringbuffer operations and does not serialize access outside the owning ringbuffer instance.

A store failure during store(long, Object) prevents the item from being appended in memory so persisted sequence state does not lag the ringbuffer. Reads for sequences no longer present in memory may call load(long).

Method Summary

Modifier and Type	Method	Description
long	getLargestSequence()	Return the largest sequence currently known to the store.
@Nullable T	load(long sequence)	Load a previously persisted item by sequence.
void	store(long sequence, T data)	Persist one item with its sequence.
default void	storeAll(long firstItemSequence, List<? extends T> items)	Persist multiple consecutive items.

Method Details

store

void store(long sequence,
 T data)

Persist one item with its sequence.

Parameters:

sequence - monotonically increasing ringbuffer sequence

data - item to persist

storeAll

default void storeAll(long firstItemSequence,
 List<? extends T> items)

Persist multiple consecutive items. Override when the backing store can batch writes more efficiently.

Parameters:

firstItemSequence - sequence of the first item

items - consecutive items to persist

load

@Nullable T load(long sequence)

Load a previously persisted item by sequence.

Parameters:

sequence - sequence to load

Returns:

persisted item, or null when absent

getLargestSequence

long getLargestSequence()

Return the largest sequence currently known to the store.

Return -1 when the store is empty or cannot determine a largest sequence. LoomCache uses this during store wire-up to make the next append continue after already persisted data.

Returns:

largest persisted sequence, or -1