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/*-
* Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This file was distributed by Oracle as part of a version of Oracle Berkeley
* DB Java Edition made available at:
*
* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
*
* Please see the LICENSE file included in the top-level directory of the
* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
* license and additional information.
*/
package com.sleepycat.je.utilint;
import java.util.Calendar;
import com.sleepycat.je.EnvironmentConfig;
/**
* This class aims to parser {@link EnvironmentConfig#VERIFY_SCHEDULE} which
* is a cron-style expression.
*
* The cron-style expression can be very complicate, for example containing
* *, ?, / and so on. But now we only handle the simplest situation. We will
* continually add the code to handle more complicated situations if needed
* in the future.
*
* Constraint for current version:
*
* - The standard string should be "* * * * *", i.e. there are 5 fields and
* 4 blank space
*
- Each filed can only be an int value or *.
*
- Can not specify dayOfMonth and dayOfWeek simultaneously
*
- Can not specify dayOfMonth or month. Because if so, we will need to
* consider the days of that month and furthermore whether that year is
* leap year for February. The difference of the number of days for
* each month make it complicate to calculate the delay and the interval.
*
- If the field is an int value, then the value should be in
* the correct range, i.e. minute(0-59), hour(0-23), dayOfWeek(0-6),
* where dayOfMonth(1-31) and month(1-12) can not be specified.
*
- If dayOfWeek is a concrete value, then minute or hour can not be '*'.
* For example, we can not use "0 * * * 5", i.e. we can not specify that
* we want the verifier to run every hour only on Friday. Because it may
* be complicate to calculate the stop time point and at least we need
* to add a variable.
*
- The same reason, if hour is a concrete value, minute can not be '*'.
*
*/
public class CronScheduleParser {
private static final String errorMess =
"The format of " + EnvironmentConfig.VERIFY_SCHEDULE +
" is invalid. ";
private static final int spaceNum = 4;
private static final int fieldNum = 5;
public static final String nullCons = "The argument should not be null.";
public static final String cons1 =
"The standard string should be '* * * * *', i.e. there are " +
fieldNum + " fields and " + spaceNum + " blank spaces.";
public static final String cons2 =
"Each field can only be an int value or *.";
public static final String cons3 =
"Can not specify dayOfWeek and dayOfMonth simultaneously.";
public static final String cons4 = "Can not specify dayOfMonth or month.";
public static final String cons5 = "Range Error: ";
public static final String cons6 =
"If the day of the week is a concrete day, then the minute and the " +
"hour should also be concrete.";
public static final String cons7 =
"If the hour is a concrete day, then minute should also be concrete";
private static final long millsOneDay = 24 * 60 * 60 * 1000;
private static final long millsOneHour = 60 * 60 * 1000;
private static final long millsOneMinute = 60 * 1000;
/** A test hook called to allow tests to supply a calendar. */
public static volatile TestHook setCurCalHook;
private final long time;
private long delay;
private long interval;
/**
* Creates an instance that uses the default calendar. The constructor will
* first validate the cron-style string and then parse the string to get
* the interval of the cron-style task represented by the string and to get
* the wait-time(delay) to first time start the cron-style task.
*
* @param cronSchedule the cron-style string
* @throws IllegalArgumentException if there is a problem with the format
* of the parameter
*/
public CronScheduleParser(final String cronSchedule) {
this(cronSchedule, Calendar.getInstance());
}
/**
* Creates an instance that uses the specified calendar. The construction
* function will first validate the cron-style string and then parse the
* string to get the interval of the cron-style task represented by the
* string and to get the wait-time(delay) to first time start the
* cron-style task.
*
* @param cronSchedule the cron-style string
* @param calendar the calendar
* @throws IllegalArgumentException if there is a problem with the format
* of the cronSchedule parameter
*/
public CronScheduleParser(final String cronSchedule,
final Calendar calendar) {
final Calendar curCal = (setCurCalHook != null) ?
setCurCalHook.getHookValue() :
calendar;
time = curCal.getTimeInMillis();
validate(cronSchedule);
parser(cronSchedule, curCal);
}
/**
* Check whether two cron-style strings are same, i.e. both are null or
* the content of the two strings are same.
*
* @param cronvSchedule1 The first cron-style string.
* @param cronSchedule2 The second cron-style string.
*
* @return true if the two cron-style strings are same.
*/
public static boolean checkSame(
final String cronvSchedule1,
final String cronSchedule2) {
if (cronvSchedule1 == null && cronSchedule2 ==null) {
return true;
}
if (cronvSchedule1 == null || cronSchedule2 ==null) {
return false;
}
if (cronvSchedule1.equals(cronSchedule2)) {
return true;
}
return false;
}
/**
* Returns the time used when computing the delay time.
*/
public long getTime() {
return time;
}
/**
* @return delay The wait-time to first time start the cron-style task
* represented by the cron-style string.
*/
public long getDelayTime() {
return delay;
}
/**
* Returns the number of milliseconds between times that match the crontab
* entry. Returns:
*
* - 7 days if day-of-week is concrete, else
*
- 1 day if hour is concrete, else
*
- 1 hour if minute is concrete, else
*
- 1 minute otherwise.
*
*
* @return interval The interval of the cron-style task represented by the
* cron-style string.
*/
public long getInterval() {
return interval;
}
private void assertDelay() {
if (delay < 0) {
throw new IllegalStateException(
"Delay is negative: " + delay + "; interval is: " + interval);
}
}
private void parser(final String cronSchedule, Calendar curCal) {
int curDayOfWeek = curCal.get(Calendar.DAY_OF_WEEK);
int curHour = curCal.get(Calendar.HOUR_OF_DAY);
int curMinute = curCal.get(Calendar.MINUTE);
/*
* Previously, we use Calendar.getInstance() to initialize scheduleCal,
* which aims to let scheduleCal have some similar/same attributes
* with curCal, such as the day of the week. But we may use
* setCurCalHook.doHook to set curCal to be a future week, now
* using Calendar.getInstance() can not achieve the original purpose.
*/
Calendar scheduleCal = (Calendar) curCal.clone();
scheduleCal.set(Calendar.SECOND, 0);
scheduleCal.set(Calendar.MILLISECOND, 0);
String[] timeArray = cronSchedule.split(" ");
/* dayofWeek is a concrete value. */
if (!timeArray[4].equals("*")) {
interval = 7 * millsOneDay;
int tmpDayOfWeek = Integer.valueOf(timeArray[4]) + 1;
int tmpHour = Integer.valueOf(timeArray[1]);
int tmpMinute = Integer.valueOf(timeArray[0]);
scheduleCal.set(Calendar.DAY_OF_WEEK, tmpDayOfWeek);
scheduleCal.set(Calendar.HOUR_OF_DAY, tmpHour);
scheduleCal.set(Calendar.MINUTE, tmpMinute);
if (scheduleCal.getTimeInMillis() < curCal.getTimeInMillis()) {
/* add 7 days to set next week */
scheduleCal.add(Calendar.DATE, 7);
}
delay = scheduleCal.getTimeInMillis() - curCal.getTimeInMillis();
assertDelay();
return;
}
if (!timeArray[1].equals("*")) {
interval = millsOneDay;
int tmpHour = Integer.valueOf(timeArray[1]);
int tmpMinute = Integer.valueOf(timeArray[0]);
/*
* Guarantee that both dayOfWeek is same when dayOfWeek is * in
* cronSchedule.
*/
scheduleCal.set(Calendar.DAY_OF_WEEK, curDayOfWeek);
scheduleCal.set(Calendar.HOUR_OF_DAY, tmpHour);
scheduleCal.set(Calendar.MINUTE, tmpMinute);
if (scheduleCal.getTimeInMillis() < curCal.getTimeInMillis()) {
/* to set next day */
scheduleCal.add(Calendar.DATE, 1);
}
delay = scheduleCal.getTimeInMillis() - curCal.getTimeInMillis();
assertDelay();
return;
}
if (!timeArray[0].equals("*")) {
interval = millsOneHour;
int tmpMinute = Integer.valueOf(timeArray[0]);
/*
* Guarantee that both dayOfWeek and both hour are same whe
* dayOfWeek and hour are * in cronSchedule.
*/
scheduleCal.set(Calendar.DAY_OF_WEEK, curDayOfWeek);
scheduleCal.set(Calendar.HOUR_OF_DAY, curHour);
scheduleCal.set(Calendar.MINUTE, tmpMinute);
if (scheduleCal.getTimeInMillis() < curCal.getTimeInMillis()) {
/* to set next hour */
scheduleCal.add(Calendar.HOUR, 1);
}
delay = scheduleCal.getTimeInMillis() - curCal.getTimeInMillis();
assertDelay();
return;
}
if (timeArray[0].equals("*")) {
interval = millsOneMinute;
delay = 0;
assertDelay();
return;
}
}
private void validate(final String cronSchedule) {
if (cronSchedule == null) {
throw new IllegalArgumentException(errorMess + nullCons);
}
/*
* Constraint 1: The standard string should be "* * * * *", i.e.
* there are 5 fields and 4 blank space.
*/
int spaceCount = 0;
for (int i = 0; i < cronSchedule.length(); i++) {
char c = cronSchedule.charAt(i);
if (c == 32 ) { /* The ASCII value of ' ' is 32. */
spaceCount++;
}
}
if (spaceCount != spaceNum ||
cronSchedule.split(" ").length != fieldNum) {
throw new IllegalArgumentException(errorMess + cons1);
}
String[] timeArray = cronSchedule.split(" ");
/*
* Constraint 2: Each filed can only be an int value or *.
*/
for (String str : timeArray) {
try {
Integer.valueOf(str);
} catch (NumberFormatException e) {
if (!str.equals("*")) {
throw new IllegalArgumentException(errorMess + cons2);
}
}
}
/*
* Constraint 3: Can not specify dayOfMonth and dayOfWeek
* simultaneously.
*/
if (!timeArray[2].equals("*") && !timeArray[4].equals("*")) {
throw new IllegalArgumentException(errorMess + cons3);
}
/*
* Constraint 4: Can not specify dayOfMonth or month.
*/
if (!timeArray[2].equals("*") || !timeArray[3].equals("*")) {
throw new IllegalArgumentException(errorMess + cons4);
}
/*
* Constraint 5: If the field is a int value, then the value should
* be in the correct range.
*/
if (!timeArray[0].equals("*")) {
int min = Integer.valueOf(timeArray[0]);
if (min < 0 || min > 59) {
throw new IllegalArgumentException
(errorMess + cons5 + "The minute should be (0-59).");
}
}
if (!timeArray[1].equals("*")) {
int hour = Integer.valueOf(timeArray[1]);
if (hour < 0 || hour > 23) {
throw new IllegalArgumentException
(errorMess + cons5 + "The hour should be (0-23).");
}
}
if (!timeArray[4].equals("*")) {
int dayOfWeek = Integer.valueOf(timeArray[4]);
if (dayOfWeek < 0 || dayOfWeek > 6) {
throw new IllegalArgumentException
(errorMess + cons5 + "The day of the week should" +
"be (0-6).");
}
}
/*
* Constraint 6: If dayOfWeek is a concrete value, then minute or
* hour can not be '*'.
*/
if (!timeArray[4].equals("*")) {
if (timeArray[0].equals("*") || timeArray[1].equals("*")) {
throw new IllegalArgumentException(errorMess + cons6);
}
}
/*
* Constraint 7: If hour is a concrete value, minute can not be '*'.
*/
if (!timeArray[1].equals("*")) {
if (timeArray[0].equals("*")) {
throw new IllegalArgumentException(errorMess + cons7);
}
}
/*
if (timeArray[0].equals("*")) {
throw new IllegalArgumentException
(errorMes + "User specify the verifier to run every minute." +
"This is too frequent.");
}
*/
}
}
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