com.sleepycat.je.utilint

Class CronScheduleParser

java.lang.Object

com.sleepycat.je.utilint.CronScheduleParser

public class CronScheduleParser
extends Object

This class aims to parser 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 '*'.

Field Summary

Fields

Modifier and Type	Field and Description
static String	cons1
static String	cons2
static String	cons3
static String	cons4
static String	cons5
static String	cons6
static String	cons7
static String	nullCons
static TestHook<Calendar>	setCurCalHook A test hook called to allow tests to supply a calendar.

Constructor Summary

Constructors

Constructor and Description
CronScheduleParser(String cronSchedule) Creates an instance that uses the default calendar.
CronScheduleParser(String cronSchedule, Calendar calendar) Creates an instance that uses the specified calendar.

Method Summary

Modifier and Type	Method and Description
static boolean	checkSame(String cronvSchedule1, String cronSchedule2) Check whether two cron-style strings are same, i.e.
long	getDelayTime()
long	getInterval() Returns the number of milliseconds between times that match the crontab entry.
long	getTime() Returns the time used when computing the delay time.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

nullCons

public static final String nullCons

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Constant Field Values

cons1

public static final String cons1

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Constant Field Values

cons2

public static final String cons2

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Constant Field Values

cons3

public static final String cons3

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Constant Field Values

cons4

public static final String cons4

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Constant Field Values

cons5

public static final String cons5

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Constant Field Values

cons6

public static final String cons6

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Constant Field Values

cons7

public static final String cons7

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Constant Field Values

setCurCalHook

public static volatile TestHook<Calendar> setCurCalHook

A test hook called to allow tests to supply a calendar.

Constructor Detail

CronScheduleParser

public CronScheduleParser(String cronSchedule)

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.

Parameters:

cronSchedule - the cron-style string

Throws:

IllegalArgumentException - if there is a problem with the format of the parameter

CronScheduleParser

public CronScheduleParser(String cronSchedule,
                          Calendar calendar)

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.

Parameters:

cronSchedule - the cron-style string

calendar - the calendar

Throws:

IllegalArgumentException - if there is a problem with the format of the cronSchedule parameter

Method Detail

checkSame

public static boolean checkSame(String cronvSchedule1,
                                String cronSchedule2)

Check whether two cron-style strings are same, i.e. both are null or the content of the two strings are same.

Parameters:

cronvSchedule1 - The first cron-style string.

cronSchedule2 - The second cron-style string.

Returns:

true if the two cron-style strings are same.

getTime

public long getTime()

Returns the time used when computing the delay time.

getDelayTime

public long getDelayTime()

Returns:

delay The wait-time to first time start the cron-style task represented by the cron-style string.

getInterval

public long getInterval()

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.

Returns:

interval The interval of the cron-style task represented by the cron-style string.