    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    import org.apache.tapestry5.ioc.internal.services.cron.CronExpression;
    018
    019    import java.text.ParseException;
    020    import java.util.Date;
    021
    022    public class CronSchedule implements Schedule
    023    {
    024        private CronExpression cron;
    025
    026        public CronSchedule(String cronExpression)
    027        {
    028            try
    029            {
    030                this.cron = new CronExpression(cronExpression);
    031            } catch (ParseException e)
    032            {
    033                throw new RuntimeException(e);
    034            }
    035        }
    036
    037        public long firstExecution()
    038        {
    039            return getNextValidTimeAfterNow();
    040        }
    041
    042        public long nextExecution(long previousExecution)
    043        {
    044            return getNextValidTimeAfterNow();
    045        }
    046
    047        private long getNextValidTimeAfterNow()
    048        {
    049            final Date time = cron.getNextValidTimeAfter(new Date());
    050
    051            return time == null ? 0 : time.getTime();
    052        }
    053    }