/**************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* 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.schedule;
/**
* This class acts as a buckets for sorting schedule service callbacks that are scheduled to occur at the same
* time. Each buckets constists of {@link ScheduleSlot} slots that callbacks are
* assigned to.
* <p>
* At the time of timer evaluation, callbacks that become triggerable are ordered using the bucket
* as the first-level order, and slot as the second-level order.
* <p>
* Each statement at statement creation time allocates a buckets, and each timer within the
* statement allocates a slot. Thus statements that depend on other statements (such as for insert-into),
* and timers within their statement (such as time window or output rate limit timers) behave
* deterministically.
*/
public class ScheduleBucket
{
private final int bucketNum;
private int lastSlot;
/**
* Ctor.
* @param bucketNum is a simple integer number for this bucket by which buckets can be sorted
*/
public ScheduleBucket(int bucketNum)
{
this.bucketNum = bucketNum;
lastSlot = 0;
}
/**
* Restart bucket slot numbering wuch as when a statement is restarted and new slots are allocated.
*/
public void restart()
{
lastSlot = 0;
}
/**
* Returns a new slot in the bucket.
* @return slot
*/
public ScheduleSlot allocateSlot()
{
return new ScheduleSlot(bucketNum, lastSlot++);
}
/**
* Returns a new slot in the bucket, given a slot number
* @return slot
*/
public ScheduleSlot allocateSlot(int slotNumber)
{
return new ScheduleSlot(bucketNum, slotNumber);
}
}