Package dev.getelements.elements.rt.transact

Interface Snapshot

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

StandardSnapshot

public interface Snapshot
extends AutoCloseable

Represents a loaded and limited snapshot of the database. In order to provide fine-grained access, this specifies a subset of Path and ResourceId instances which must be locked. Changes to the Snapshot only happen in memory and do not write data to disk.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	Snapshot.Builder	Builds an instance of Snapshot.

Method Summary

Modifier and Type	Method	Description
ResourceEntry	add(ResourceId resourceId)	Adds a new ResourceEntry with the supplied ResourceId, returning the result.
void	close()	Closes this snapshot, releasing any underlying system resources associated with this snapshot.
Optional<ResourceEntry>	findResourceEntry(ResourceId resourceId)	Finds the ResourceEntry at the supplied ResourceId.
Optional<ResourceEntry>	findResourceEntry(Path path)	Finds the ResourceEntry at the supplied path.
Optional<TaskEntry<ResourceId>>	findTaskEntry(ResourceId resourceId)	Finds the TaskEntry associated with the supplied ResourceId.
TaskEntry<ResourceId>	getOrCreateTaskEntry(ResourceId resourceId)	Gets the TaskEntry or throws an instance of SnapshotMissException.
Collection<ResourceEntry>	getResourceEntries()	Gets all ResourceEntry instances in this Snapshot.
default ResourceEntry	getResourceEntry(ResourceId resourceId)	Gets the ResourceEntry or throws an instance of SnapshotMissException.
default ResourceEntry	getResourceEntry(Path path)	Gets the ResourceEntry or throws an instance of SnapshotMissException.
Collection<TaskEntry<?>>	getTaskEntries()	Gets all TaskEntry instances in this Snapshot.
Stream<ResourceService.Listing>	list(Path path)	List all ResourceEntry instances matching the Path.

Method Details

list

Stream<ResourceService.Listing> list(Path path)

List all ResourceEntry instances matching the Path. As a Snapshot may be backed by a Stream from the DataStore, it is required that the Stream reach a terminal state or be explicitly closed. Closing this Snapshot will close the stream associatd with it.

Parameters:

path - the path

Returns:

the Stream<ResourceEntry>

findTaskEntry

Optional<TaskEntry<ResourceId>> findTaskEntry(ResourceId resourceId)

Finds the TaskEntry associated with the supplied ResourceId.

Parameters:

resourceId - the ResourceId

Returns:

the Optional containing the TaskEntry<ResourceId>

getOrCreateTaskEntry

TaskEntry<ResourceId> getOrCreateTaskEntry(ResourceId resourceId)

Gets the TaskEntry or throws an instance of SnapshotMissException.

Parameters:

resourceId - the path

Returns:

the Optional containing a TaskEntry never null

getResourceEntry

default ResourceEntry getResourceEntry(Path path)

Gets the ResourceEntry or throws an instance of SnapshotMissException.

Parameters:

path - the Resource id

Returns:

the ResourceEntry, never null

findResourceEntry

Optional<ResourceEntry> findResourceEntry(Path path)

Finds the ResourceEntry at the supplied path.

Parameters:

path - the path

Returns:

an Optional containing the Entry.

getResourceEntry

default ResourceEntry getResourceEntry(ResourceId resourceId)

Gets the ResourceEntry or throws an instance of SnapshotMissException.

Parameters:

resourceId - the Resource id

Returns:

the ResourceEntry, never null

Throws:

SnapshotMissException - if the snapshot entry was never loaded

findResourceEntry

Optional<ResourceEntry> findResourceEntry(ResourceId resourceId)

Finds the ResourceEntry at the supplied ResourceId.

Parameters:

resourceId - the path

Returns:

an Optional containing the Entry.

getTaskEntries

Collection<TaskEntry<?>> getTaskEntries()

Gets all TaskEntry instances in this Snapshot.

Returns:

gets all TaskEntry instances associated with this Snapshot

getResourceEntries

Collection<ResourceEntry> getResourceEntries()

Gets all ResourceEntry instances in this Snapshot.

Returns:

gets all ResourceEntry instances associated with this Snapshot

add

ResourceEntry add(ResourceId resourceId)

Adds a new ResourceEntry with the supplied ResourceId, returning the result. Any previously accessed ResourceEntry instances.

Parameters:

resourceId - the ResourceId

Returns:

the ResourceEntry which was added.

Throws:

SnapshotMissException - if the snapshot entry was never loaded

DuplicateException - if a ResourceId already exists

close

void close()

Closes this snapshot, releasing any underlying system resources associated with this snapshot.

Specified by:

close in interface AutoCloseable