    001// Copyright 2011 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.ioc.services.cron;
    016
    017/**
    018 * Used with {@link PeriodicExecutor} to control the schedule for when jobs execute.
    019 */
    020public interface Schedule
    021{
    022    /**
    023     * For a newly created job, what is the start time for the job.  Often, the current clock time is returned, to start
    024     * a job as soon as possible.
    025     *
    026     * @return start time for new job, in system clock millis
    027     */
    028    long firstExecution();
    029
    030    /**
    031     * Computes the next execution time for a job.
    032     *
    033     * @param previousExecution time of previous execution (in system clock millis)
    034     * @return time of next execution (in system clock millis)
    035     */
    036    long nextExecution(long previousExecution);
    037}