    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
    017import org.apache.tapestry5.ioc.internal.services.cron.CronExpression;
    018
    019import java.text.ParseException;
    020import java.util.Date;
    021
    022public 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    @Override
    038    public long firstExecution()
    039    {
    040        return getNextValidTimeAfterNow();
    041    }
    042
    043    @Override
    044    public long nextExecution(long previousExecution)
    045    {
    046        return getNextValidTimeAfterNow();
    047    }
    048
    049    private long getNextValidTimeAfterNow()
    050    {
    051        final Date time = cron.getNextValidTimeAfter(new Date());
    052
    053        return time == null ? 0 : time.getTime();
    054    }
    055}