    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     * A very simple schedule, that simply executes the desired job at fixed intervals.
    019     *
    020     * @since 5.3
    021     */
    022    public class IntervalSchedule implements Schedule
    023    {
    024        private final long interval;
    025
    026        /**
    027         * Interval at which the schedule should execute jobs. The first execution is delayed from current time
    028         * by the interval as well.
    029         *
    030         * @param interval in milliseconds
    031         */
    032        public IntervalSchedule(long interval)
    033        {
    034            assert interval > 0;
    035
    036            this.interval = interval;
    037        }
    038
    039        public long firstExecution()
    040        {
    041            return nextExecution(System.currentTimeMillis());
    042        }
    043
    044        public long nextExecution(long previousExecution)
    045        {
    046            return previousExecution + interval;
    047        }
    048    }