package com.thinkbiganalytics.scheduler.util;
/*-
* #%L
* thinkbig-commons-util
* %%
* Copyright (C) 2017 ThinkBig Analytics
* %%
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* #L%
*/
import org.quartz.CronExpression;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* Generic Cron Utility for calculating Cron Dates both Previous and Next Occurrences
*/
public class CronExpressionUtil {
private static Logger LOG = LoggerFactory.getLogger(CronExpressionUtil.class);
public static Long getCronInterval(String cronExpression) throws ParseException {
return getCronInterval(new CronExpression(cronExpression));
}
public static Long getCronInterval(CronExpression cron) {
Date nextValidTime = getNextFireTime(cron);
Date subsequentNextValidTime = getNextFireTime(nextValidTime, cron);
long interval = subsequentNextValidTime.getTime() - nextValidTime.getTime();
return interval;
}
public static Date getPreviousFireTime(String cronExpression) throws ParseException {
return getPreviousFireTime(new CronExpression(cronExpression));
}
public static Date getPreviousFireTime(CronExpression cron) {
Long interval = getCronInterval(cron);
Date nextValidTime = getNextFireTime(cron);
return new Date(nextValidTime.getTime() - interval);
}
public static Date getPreviousFireTime(CronExpression cron, int previousNumber) {
if (previousNumber <= 0) {
previousNumber = 1;
}
List<Date> dates = getPreviousFireTimes(cron, previousNumber);
return dates.get(previousNumber - 1);
}
public static Date getPreviousFireTime(Date lastFireTime, String cronExpression) throws ParseException {
return getPreviousFireTime(lastFireTime, new CronExpression(cronExpression));
}
public static Date getPreviousFireTime(Date lastFireTime, CronExpression cron) {
Long interval = getCronInterval(cron);
Date nextValidTime = getNextFireTime(lastFireTime, cron);
return new Date(nextValidTime.getTime() - interval);
}
public static Date getNextFireTime(String cronExpression) throws ParseException {
return getNextFireTime(new CronExpression(cronExpression));
}
public static Date getNextFireTime(CronExpression cron) {
return cron.getNextValidTimeAfter(new Date());
}
public static Date getNextFireTime(Date lastFireTime, String cronExpression) throws ParseException {
return getNextFireTime(lastFireTime, new CronExpression(cronExpression));
}
public static Date getNextFireTime(Date lastFireTime, CronExpression cron) {
return cron.getNextValidTimeAfter(lastFireTime);
}
public static List<Date> getNextFireTimes(String cronExpression, Integer count) throws ParseException {
return getNextFireTimes(new CronExpression(cronExpression), count);
}
public static List<Date> getNextFireTimes(CronExpression cron, Integer count) throws ParseException {
List<Date> dates = new ArrayList<Date>();
Date lastDate = new Date();
for (int i = 0; i < count; i++) {
Date nextDate = cron.getNextValidTimeAfter(lastDate);
dates.add(nextDate);
lastDate = nextDate;
}
return dates;
}
public static List<Date> getPreviousFireTimes(String cronExpression, Integer count) throws ParseException {
return getPreviousFireTimes(new CronExpression(cronExpression), count);
}
public static List<Date> getPreviousFireTimes(CronExpression cron, Integer count) {
List<Date> dates = new ArrayList<Date>();
Long interval = getCronInterval(cron);
Date nextFireTime = getNextFireTime(cron);
for (int i = 0; i < count; i++) {
Date previous = new Date(nextFireTime.getTime() - interval);
dates.add(previous);
nextFireTime = previous;
}
return dates;
}
public static CronExpression timerToCronExpression(String timer) throws ParseException {
return TimerToCronExpression.timerToCronExpression(timer);
}
public static String timerToCronString(String timer) {
try {
CronExpression cronExpression = timerToCronExpression(timer);
return cronExpression.getCronExpression();
} catch (ParseException e) {
LOG.error("Unable to create CronExpression from timer {}. Error: {}", timer, e.getMessage(), e);
}
return null;
}
}