Interface MetadataSnapshot

All Superinterfaces:

AutoCloseable

public interface MetadataSnapshot
extends AutoCloseable

An immutable, store-issued view of one committed metadata revision.

Reads and scans never observe later commits. The snapshot and all live objects it issues remain bound to the exact issuing store instance.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final record	MetadataSnapshot.Integrity	Stable content-integrity metadata without payload or storage details.
static final record	MetadataSnapshot.KeyRange	An ordered range within one semantic namespace.
static interface	MetadataSnapshot.Record	A repeatable record view owned by a snapshot.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes this snapshot idempotently and invalidates its cursors.
Optional<MetadataSnapshot.Record>	get(MetadataKey key)	Reads one record from this stable view.
Optional<MetadataKey>	greatestKey(String namespace)	Returns the greatest key in one namespace without opening record content.
long	revision()	Returns the captured non-negative committed store revision.
MetadataCursor	scan(MetadataSnapshot.KeyRange range, CancellationSignal cancellation)	Opens a lazy deterministic scan over this stable view.
MetadataStoreId	storeId()	Returns the issuing store identity.

Method Details

storeId

MetadataStoreId storeId()

Returns the issuing store identity.

Returns:

store identity

revision

long revision()

Returns the captured non-negative committed store revision.

Returns:

snapshot revision

get

Optional<MetadataSnapshot.Record> get(MetadataKey key)
                               throws IOException

Reads one record from this stable view.

Parameters:

key - semantic record identity

Returns:

the stable record, or empty when absent

Throws:

IOException - when content metadata cannot be opened

MetadataStoreException - when this snapshot is closed or foreign

greatestKey

Optional<MetadataKey> greatestKey(String namespace)

Returns the greatest key in one namespace without opening record content.

Parameters:

namespace - canonical metadata namespace

Returns:

greatest snapshot key, or empty when the namespace is empty

Throws:

IllegalStateException - when this snapshot is closed or foreign

scan

MetadataCursor scan(MetadataSnapshot.KeyRange range,
 CancellationSignal cancellation)
             throws IOException

Opens a lazy deterministic scan over this stable view.

Parameters:

range - ordered semantic range

cancellation - cooperative cancellation signal

Returns:

store-issued cursor

Throws:

IOException - when the scan cannot be opened

MetadataStoreException - when this snapshot is closed or foreign

close

void close()

Closes this snapshot idempotently and invalidates its cursors.

Specified by:

close in interface AutoCloseable