Package com.vaadin.collaborationengine

Class LocalBackend

java.lang.Object

com.vaadin.collaborationengine.Backend

com.vaadin.collaborationengine.LocalBackend

public class LocalBackend
extends Backend

A simple backend implementation that only distributes events locally and assumes that there is no previous history for event logs.

Author:

Vaadin Ltd

Nested Class Summary

Nested classes/interfaces inherited from class com.vaadin.collaborationengine.Backend

Backend.EventIdNotFoundException, Backend.EventLog, Backend.Snapshot

Constructor Summary

Constructors

Constructor	Description
LocalBackend()

Method Summary

Modifier and Type	Method	Description
Registration	addMembershipListener(MembershipListener membershipListener)	Adds a listener of membership events.
UUID	getNodeId()	Gets the unique identifier of this backend node.
CompletableFuture<Backend.Snapshot>	loadLatestSnapshot(String name)	Loads the latest snapshot of data identified by the given name.
Backend.EventLog	openEventLog(String topicId)	Opens an event log with the given id.
CompletableFuture<Void>	replaceSnapshot(String name, UUID expectedId, UUID newId, String payload)	Submits a snapshot payload of data identified by the given name.

Methods inherited from class com.vaadin.collaborationengine.Backend

getCollaborationEngine, setCollaborationEngine

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LocalBackend

public LocalBackend()

Method Detail

openEventLog

public Backend.EventLog openEventLog(String topicId)

Description copied from class: Backend

Opens an event log with the given id. The returned object can be used to capture any common state related to this particular event log. An actual underlying connection is not needed until Backend.EventLog.subscribe(UUID, BiConsumer)} is invoked, but it is still recommended to make this method fail fast in case it would not be possible to open an actual underlying connection later.

Specified by:

openEventLog in class Backend

Parameters:

topicId - the id of the event log to open, not null

Returns:

an object representing the event log, not null

addMembershipListener

public Registration addMembershipListener(MembershipListener membershipListener)

Description copied from class: Backend

Adds a listener of membership events. The listener will be notified of events dispatched when a node joins or leaves the backend.

Specified by:

addMembershipListener in class Backend

Parameters:

membershipListener - the listener, not null

Returns:

a registration that can be used to remove the listener, not null

getNodeId

public UUID getNodeId()

Description copied from class: Backend

Gets the unique identifier of this backend node.

Specified by:

getNodeId in class Backend

Returns:

the node id, not null

loadLatestSnapshot

public CompletableFuture<Backend.Snapshot> loadLatestSnapshot(String name)

Description copied from class: Backend

Loads the latest snapshot of data identified by the given name. To submit a snapshot see Backend.replaceSnapshot(String, UUID, UUID, String).

Specified by:

loadLatestSnapshot in class Backend

Parameters:

name - the name identifying the data, not null

Returns:

a completable future resolved with the UUID and snapshot, not null

replaceSnapshot

public CompletableFuture<Void> replaceSnapshot(String name,
                                               UUID expectedId,
                                               UUID newId,
                                               String payload)

Description copied from class: Backend

Submits a snapshot payload of data identified by the given name. The latest submitted snapshot for that name can be loaded with Backend.loadLatestSnapshot(String).

Specified by:

replaceSnapshot in class Backend

Parameters:

name - the name identifying the date, not null

expectedId - the unique ID of the expected current snapshot

newId - the unique ID that the new snapshot will be stored with, not null

payload - the snapshot payload, not null

Returns:

a completable future that will be resolved when the operation completes, not null