io.realm

Interface SyncSession.ErrorHandler

Enclosing class:

SyncSession

public static interface SyncSession.ErrorHandler

Interface used to report any session errors.

See Also:

SyncManager#setDefaultSessionErrorHandler(ErrorHandler), SyncConfiguration.Builder#errorHandler(ErrorHandler)

Method Summary

Modifier and Type	Method and Description
void	onError(SyncSession session, ObjectServerError error) Callback for errors on a session object.

Method Detail

onError

void onError(SyncSession session,
             ObjectServerError error)

Callback for errors on a session object. It is not allowed to throw an exception inside an error handler. If the operations in an error handler can throw, it is safer to catch any exception in the error handler. When an exception is thrown in the error handler, the occurrence will be logged and the exception will be ignored.

When the error.getErrorCode() returns ErrorCode.CLIENT_RESET, it indicates the Realm needs to be reset and the error can be cast to ClientResetRequiredError.

A synced Realm may need to be reset because the Realm Object Server encountered an error and had to be restored from a backup. If the backup copy of the remote Realm is of an earlier version than the local copy of the Realm, the server will ask the client to reset the Realm.

The reset process is as follows: the local copy of the Realm is copied into a recovery directory for safekeeping, and then deleted from the original location. The next time the Realm for that URL is opened, the Realm will automatically be re-downloaded from the Realm Object Server, and can be used as normal.

Data written to the Realm after the local copy of the Realm diverged from the backup remote copy will be present in the local recovery copy of the Realm file. The re-downloaded Realm will initially contain only the data present at the time the Realm was backed up on the server.

The client reset process can be initiated in one of two ways:

1. Run ClientResetRequiredError.executeClientReset() manually. All Realm instances must be closed before this method is called.
2. If Client Reset isn't executed manually, it will automatically be carried out the next time all Realm instances have been closed and re-opened. This will most likely be when the app is restarted.

WARNING: Any writes to the Realm file between this callback and Client Reset has been executed, will not be synchronized to the Object Server. Those changes will only be present in the backed up file. It is therefore recommended to close all open Realm instances as soon as possible.

Parameters:

session - SyncSession this error happened on.

error - type of error.