    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
    015    package org.apache.tapestry5.ioc.services.cron;
    016
    017    /**
    018     * Used with {@link PeriodicExecutor} to control the schedule for when jobs execute.
    019     */
    020    public 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    }