/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
package com.espertech.esper.client;
/**
* Defines an interface to notify of new and old events.
* <p>
* Also see {@link StatementAwareUpdateListener} for update listeners that require
* the statement and service provider instance to be passed to the listener in addition to events.
*/
public interface UpdateListener {
/**
* Notify that new events are available or old events are removed.
* If the call to update contains new (inserted) events, then the first argument will be a non-empty list and
* the second will be empty. Similarly, if the call is a notification of deleted events, then the first argument
* will be empty and the second will be non-empty.
* <p>
* Either the newEvents or oldEvents will be non-null. This method won't be called with both arguments being null
* (unless using output rate limiting or force-output options),
* but either one could be null. The same is true for zero-length arrays.
* Either newEvents or oldEvents will be non-empty. If both are non-empty, then the update is a modification
* notification.
*
* @param newEvents is any new events. This will be null or empty if the update is for old events only.
* @param oldEvents is any old events. This will be null or empty if the update is for new events only.
*/
public void update(EventBean[] newEvents, EventBean[] oldEvents);
}