CallbackHandler API

The CallbackHandler interface is invoked when any database event occurs. A default callback handler is provided, which basically does nothing. You should implement a custom CallbackHandler to register important events. The callback is invoked on the thread that is processing the event. To receive callbacks for database changes, you must register a CallBackHandler with the generated database class, the entity class, or both. You can create a handler by extending the DefaultCallbackHandler class or by implementing the com.sybase.persistence.CallbackHandler interface.

In your handler, override the particular callback that you are interested in (for example, void onReplayFailure(java.lang.Object entity) ). The callback is executed in the thread that is performing the action (for example, replay). When you receive the callback, the particular activity is already complete.

Callbacks in the CallbackHandler Interface
Callback	Description
void onReplayFailure(java.lang.Object entity)	This method is invoked when a replay request fails. Note: CallbackHandlers registered for both the MBO class of the entity and the Package DB are invoked. Parameters: entity – the Mobile Business Object to replay.
void onReplaySuccess(java.lang.Object entity)	This method is invoked when a replay request succeeds. Note: CallbackHandlers registered for both the MBO class of the entity and the Package DB are invoked. Parameters: entity – the Mobile Business Object to replay.
int onSynchronize(ObjectList groups, SynchronizationContext context)	This method is invoked at different stages of the synchronization. The status of the synchronization context specifies the stage of the synchronization. Parameters: groups – a list of synchronization groups. context – the synchronization context. Returns: Either SynchronizationAction.CONTINUE or Synchronization.CANCEL. If SynchronizationAction.CANCEL is returned, the synchronize is cancelled if the status of the synchronization context is one of the following. SynchronizationStatus.STARTING SynchronizationStatus.ASYNC_REPLAY_COMPLETED SynchronizationStatus.STARTING_ON_NOTIFICATION The return value has no effect if the status is not in the above list.
void onMessageException(java.lang.Exception ex)	This method is invoked when an exception occurs in the processing of a message. Note: In DefaultCallbackHandlers, onMessageException re-throws the Exception so that the messaging layer can retry the message. The application developer has the option to implement a custom CallbackHandler that does not re-throw the exception, based on exception types or other conditions, so that the message is not retried. Parameters: ex – the exception thrown when processing a message.

This code shows how to create and register a handler to receive callbacks:

public class MyCallbackHandler extends DefaultCallbackHandler
{
    // implementation
}

CallbackHandler handler = new MyCallbackHandler();
<PkgName>DB.registerCallbackHandler(handler);