Package io.realm.mongodb.sync

Interface DiscardUnsyncedChangesStrategy

All Superinterfaces:

AutomaticClientResetStrategy, SyncClientResetStrategy

public interface DiscardUnsyncedChangesStrategy
extends AutomaticClientResetStrategy

Strategy that automatically resolves a Client Reset by discarding any unsynced data. Unlike ManuallyRecoverUnsyncedChangesStrategy there is no need to close Realm instances before performing the client reset. Once completed changes will be reported through the normal collection and object notifications.

A synced Realm may need to be reset because the MongoDB Realm Server encountered an error and had to be restored from a backup or because it has been too long since the client connected to the server so the server has rotated the logs.

The Client Reset thus occurs because the server does not have the full information required to bring the Client fully up to date.

The discard unsynced changes process is as follows: when a client reset is received by the client the onBeforeReset(Realm) callback is invoked, then the client would be reset. Once the reset has concluded the callback onAfterReset(Realm, Realm) would be invoked if the changes have been discarded successfully.

In the event that the client reset could not discard the unsynced data the onManualResetFallback(SyncSession, ClientResetRequiredError) would be invoked. It allows to manually resolve the reset as it would have been done in ManuallyRecoverUnsyncedChangesStrategy.onClientReset(SyncSession, ClientResetRequiredError).

Method Summary

Modifier and Type	Method	Description
void	onAfterReset(Realm before, Realm after)	Callback invoked before the Client Reset discards any unsynced changes.
void	onBeforeReset(Realm realm)	Callback that indicates a Client Reset is about to happen.
void	onError(SyncSession session, ClientResetRequiredError error)	Deprecated. Use onManualResetFallback(io.realm.mongodb.sync.SyncSession, io.realm.mongodb.sync.ClientResetRequiredError) instead.
void	onManualResetFallback(SyncSession session, ClientResetRequiredError error)	Callback that indicates the Client reset failed to complete.

Method Detail

onBeforeReset

void onBeforeReset(Realm realm)

Callback that indicates a Client Reset is about to happen. It provides a handle to the local realm before the reset.

Specified by:

onBeforeReset in interface AutomaticClientResetStrategy

Parameters:

realm - frozen Realm in its state before the reset.

onAfterReset

void onAfterReset(Realm before,
                  Realm after)

Callback invoked before the Client Reset discards any unsynced changes. It provides two Realm instances, a frozen one displaying the state before the reset and a regular Realm displaying the current state that can be used to recover any unsynced changes from being discarded.

Parameters:

before - Realm frozen Realm in the before after the reset.

after - Realm Realm after the reset.

onError

@Deprecated
void onError(SyncSession session,
             ClientResetRequiredError error)

Deprecated.

Use onManualResetFallback(io.realm.mongodb.sync.SyncSession, io.realm.mongodb.sync.ClientResetRequiredError) instead.

Callback that indicates the Client reset failed to complete. It should be handled as ManuallyRecoverUnsyncedChangesStrategy.onClientReset(SyncSession, ClientResetRequiredError).

Parameters:

session - SyncSession this error happened on.

error - ClientResetRequiredError the specific Client Reset error.

onManualResetFallback

void onManualResetFallback(SyncSession session,
                           ClientResetRequiredError error)

Callback that indicates the Client reset failed to complete. It should be handled as ManuallyRecoverUnsyncedChangesStrategy.onClientReset(SyncSession, ClientResetRequiredError).

Specified by:

onManualResetFallback in interface AutomaticClientResetStrategy

Parameters:

session - SyncSession this error happened on.

error - ClientResetRequiredError the specific Client Reset error.