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}