it.sauronsoftware.cron4j.Predictor Maven / Gradle / Ivy
/*
* cron4j - A pure Java cron-like scheduler
*
* Copyright (C) 2007-2010 Carlo Pelliccia (www.sauronsoftware.it)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version
* 2.1, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License 2.1 for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License version 2.1 along with this program.
* If not, see
* A predictor is able to predict when a scheduling pattern will be matched.
*
*
* Suppose you want to know when the scheduler will execute a task scheduled
* with the pattern 0 3 * jan-jun,sep-dec mon-fri. You can predict the
* next n execution of the task using a Predictor instance:
*
*
*
* String pattern = "0 3 * jan-jun,sep-dec mon-fri";
* Predictor p = new Predictor(pattern);
* for (int i = 0; i < n; i++) {
* System.out.println(p.nextMatchingDate());
* }
*
*
* @author Carlo Pelliccia
* @since 1.1
*/
public class Predictor {
/**
* The scheduling pattern on which the predictor works.
*/
private SchedulingPattern schedulingPattern;
/**
* The start time for the next prediction.
*/
private long time;
/**
* The time zone for the prediction.
*/
private TimeZone timeZone = TimeZone.getDefault();
/**
* It builds a predictor with the given scheduling pattern and start time.
*
* @param schedulingPattern
* The pattern on which the prediction will be based.
* @param start
* The start time of the prediction.
* @throws InvalidPatternException
* In the given scheduling pattern isn't valid.
*/
public Predictor(String schedulingPattern, long start)
throws InvalidPatternException {
this.schedulingPattern = new SchedulingPattern(schedulingPattern);
this.time = (start / (1000 * 60)) * 1000 * 60;
}
/**
* It builds a predictor with the given scheduling pattern and start time.
*
* @param schedulingPattern
* The pattern on which the prediction will be based.
* @param start
* The start time of the prediction.
* @throws InvalidPatternException
* In the given scheduling pattern isn't valid.
*/
public Predictor(String schedulingPattern, Date start)
throws InvalidPatternException {
this(schedulingPattern, start.getTime());
}
/**
* It builds a predictor with the given scheduling pattern and the current
* system time as the prediction start time.
*
* @param schedulingPattern
* The pattern on which the prediction will be based.
* @throws InvalidPatternException
* In the given scheduling pattern isn't valid.
*/
public Predictor(String schedulingPattern) throws InvalidPatternException {
this(schedulingPattern, System.currentTimeMillis());
}
/**
* It builds a predictor with the given scheduling pattern and start time.
*
* @param schedulingPattern
* The pattern on which the prediction will be based.
* @param start
* The start time of the prediction.
* @since 2.0
*/
public Predictor(SchedulingPattern schedulingPattern, long start) {
this.schedulingPattern = schedulingPattern;
this.time = (start / (1000 * 60)) * 1000 * 60;
}
/**
* It builds a predictor with the given scheduling pattern and start time.
*
* @param schedulingPattern
* The pattern on which the prediction will be based.
* @param start
* The start time of the prediction.
* @since 2.0
*/
public Predictor(SchedulingPattern schedulingPattern, Date start) {
this(schedulingPattern, start.getTime());
}
/**
* It builds a predictor with the given scheduling pattern and the current
* system time as the prediction start time.
*
* @param schedulingPattern
* The pattern on which the prediction will be based.
* @since 2.0
*/
public Predictor(SchedulingPattern schedulingPattern) {
this(schedulingPattern, System.currentTimeMillis());
}
/**
* Sets the time zone for predictions.
*
* @param timeZone
* The time zone for predictions.
* @since 2.2.5
*/
public void setTimeZone(TimeZone timeZone) {
this.timeZone = timeZone;
}
/**
* It returns the next matching moment as a millis value.
*
* @return The next matching moment as a millis value.
*/
public synchronized long nextMatchingTime() {
// Go a minute ahead.
time += 60000;
// Is it matching?
if (schedulingPattern.match(time)) {
return time;
}
// Go through the matcher groups.
int size = schedulingPattern.matcherSize;
long[] times = new long[size];
for (int k = 0; k < size; k++) {
// Ok, split the time!
GregorianCalendar c = new GregorianCalendar();
c.setTimeInMillis(time);
c.setTimeZone(timeZone);
int minute = c.get(Calendar.MINUTE);
int hour = c.get(Calendar.HOUR_OF_DAY);
int dayOfMonth = c.get(Calendar.DAY_OF_MONTH);
int month = c.get(Calendar.MONTH);
int year = c.get(Calendar.YEAR);
// Gets the matchers.
ValueMatcher minuteMatcher = (ValueMatcher) schedulingPattern.minuteMatchers.get(k);
ValueMatcher hourMatcher = (ValueMatcher) schedulingPattern.hourMatchers.get(k);
ValueMatcher dayOfMonthMatcher = (ValueMatcher) schedulingPattern.dayOfMonthMatchers.get(k);
ValueMatcher dayOfWeekMatcher = (ValueMatcher) schedulingPattern.dayOfWeekMatchers.get(k);
ValueMatcher monthMatcher = (ValueMatcher) schedulingPattern.monthMatchers.get(k);
for (;;) { // day of week
for (;;) { // month
for (;;) { // day of month
for (;;) { // hour
for (;;) { // minutes
if (minuteMatcher.match(minute)) {
break;
} else {
minute++;
if (minute > 59) {
minute = 0;
hour++;
}
}
}
if (hour > 23) {
hour = 0;
dayOfMonth++;
}
if (hourMatcher.match(hour)) {
break;
} else {
hour++;
minute = 0;
}
}
if (dayOfMonth > 31) {
dayOfMonth = 1;
month++;
}
if (month > Calendar.DECEMBER) {
month = Calendar.JANUARY;
year++;
}
if (dayOfMonthMatcher instanceof DayOfMonthValueMatcher) {
DayOfMonthValueMatcher aux = (DayOfMonthValueMatcher) dayOfMonthMatcher;
if (aux.match(dayOfMonth, month + 1, c.isLeapYear(year))) {
break;
} else {
dayOfMonth++;
hour = 0;
minute = 0;
}
} else if (dayOfMonthMatcher.match(dayOfMonth)) {
break;
} else {
dayOfMonth++;
hour = 0;
minute = 0;
}
}
if (monthMatcher.match(month + 1)) {
break;
} else {
month++;
dayOfMonth = 1;
hour = 0;
minute = 0;
}
}
// Is this ok?
c = new GregorianCalendar();
c.setTimeZone(timeZone);
c.set(Calendar.MINUTE, minute);
c.set(Calendar.HOUR_OF_DAY, hour);
c.set(Calendar.DAY_OF_MONTH, dayOfMonth);
c.set(Calendar.MONTH, month);
c.set(Calendar.YEAR, year);
// Day-of-month/month/year compatibility check.
int oldDayOfMonth = dayOfMonth;
int oldMonth = month;
int oldYear = year;
dayOfMonth = c.get(Calendar.DAY_OF_MONTH);
month = c.get(Calendar.MONTH);
year = c.get(Calendar.YEAR);
if (month != oldMonth || dayOfMonth != oldDayOfMonth
|| year != oldYear) {
// Take another spin!
continue;
}
// Day of week.
int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);
if (dayOfWeekMatcher.match(dayOfWeek - 1)) {
break;
} else {
dayOfMonth++;
hour = 0;
minute = 0;
if (dayOfMonth > 31) {
dayOfMonth = 1;
month++;
if (month > Calendar.DECEMBER) {
month = Calendar.JANUARY;
year++;
}
}
}
}
// Seems it matches!
times[k] = (c.getTimeInMillis() / (1000 * 60)) * 1000 * 60;
}
// Which one?
long min = Long.MAX_VALUE;
for (int k = 0; k < size; k++) {
if (times[k] < min) {
min = times[k];
}
}
// Updates the object current time value.
time = min;
// Here it is.
return time;
}
/**
* It returns the next matching moment as a {@link Date} object.
*
* @return The next matching moment as a {@link Date} object.
*/
public synchronized Date nextMatchingDate() {
return new Date(nextMatchingTime());
}
}