/* This file is part of VoltDB.
* Copyright (C) 2008-2017 VoltDB Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package callcenter;
/**
* Source of events with a schedule.
*
* No threading or blocking implied.
*
* Return null if nothing is ready or present.
*/
public interface EventSource<T> {
/**
* Return the next event that is safe for delivery or null
* if there are no safe objects to deliver.
*
* Null response could mean no events, or could mean all events
* are scheduled for the future.
*
* @param systemCurrentTimeMillis The current time.
*/
public T next(long currentTimeMilliseconds);
/**
* Ignore any scheduled delays and return events in
* schedule order until empty.
*/
public T drain();
}