uws.service.file

Class EventFrequency

java.lang.Object

uws.service.file.EventFrequency

public final class EventFrequency
extends java.lang.Object

Let interpret and computing a frequency.

Frequency syntax

The frequency is expressed as a string at initialization of this object. This string must respect the following syntax:

• 'D' hh mm : daily schedule at hh:mm
• 'W' dd hh mm : weekly schedule at the given day of the week (1:sunday, 2:monday, ..., 7:saturday) at hh:mm
• 'M' dd hh mm : monthly schedule at the given day of the month at hh:mm
• 'h' mm : hourly schedule at the given minute
• 'm' : scheduled every minute (for completness :-))

Where: hh = integer between 0 and 23, mm = integer between 0 and 59, dd (for 'W') = integer between 1 and 7 (1:sunday, 2:monday, ..., 7:saturday), dd (for 'M') = integer between 1 and 31.

Warning: The frequency type is case sensitive! Then you should particularly pay attention at the case when using the frequency types 'M' (monthly) and 'm' (every minute).

Parsing errors are not thrown but "resolved" silently. The "solution" depends of the error. 2 cases of errors are considered:

• Frequency type mismatch: It happens when the first character is not one of the expected (D, W, M, h, m). That means: bad case (i.e. 'd' rather than 'D'), another character. In this case, the frequency will be: daily at 00:00.
• Parameter(s) missing or incorrect: With the "daily" frequency ('D'), at least 2 parameters must be provided ; 3 for "weekly" ('W') and "monthly" ('M') ; only 1 for "hourly" ('h') ; none for "every minute" ('m'). This number of parameters is a minimum: only the n first parameters will be considered while the others will be ignored. If this minimum number of parameters is not respected or if a parameter value is incorrect, all parameters will be set to their default value (which is 0 for all parameter except dd for which it is 1).

Examples:

• "" or NULL = every day at 00:00
• "D 06 30" or "D 6 30" = every day at 06:30
• "D 24 30" = every day at 00:00, because hh must respect the rule: 0 ≤ hh ≤ 23
• "d 06 30" or "T 06 30" = every day at 00:00, because the frequency type "d" (lower case of "D") or "T" do not exist
• "W 2 6 30" = every week on Tuesday at 06:30
• "W 8 06 30" = every week on Sunday at 00:00, because with 'W' dd must respect the rule: 1 ≤ dd ≤ 7
• "M 2 6 30" = every month on the 2nd at 06:30
• "M 32 6 30" = every month on the 1st at 00:00, because with 'M' dd must respect the rule: 1 ≤ dd ≤ 31
• "M 5 6 30 12" = every month on the 5th at 06:30, because at least 3 parameters are expected and so considered: "12" and eventual other parameters are ignored

Computing next event date

When this class is initialized with a frequency, it is able to compute the date of the event following a given date. The functions nextEvent() and nextEvent(Date) will compute this next event date from, respectively, now (current date/time) and the given date (the date of the last event). Both are computing the date of the next event by "adding" the frequency to the given date. And finally, the computed date is stored and returned.

Then, you have 2 possibilities to trigger the desired event:

• By calling isTimeElapsed(), you can test whether at the current moment the date of the next event has been reached or not. In function of the value returned by this function you will be then able to process the desired action or not.
• By creating a Timer with the next date event. Thus, the desired action will be automatically triggered at the exact moment.

Since:

4.4

Version:

4.4 (07/2018)

Author:

Marc Wenger (CDS), Grégory Mantelet (ARI;CDS)

Constructor Summary

Constructors

Constructor and Description
EventFrequency(java.lang.String interval) Create a new event frequency.

Method Summary

Modifier and Type	Method and Description
java.lang.String	getEventID() Get a string which identity the period between the last event and the next one (whose the date has been computed by this object).
java.util.Date	getNextEvent() Get the date of the next event.
boolean	isTimeElapsed() Tell whether the interval between the last event and now is greater or equals to the frequency represented by this object.
java.util.Date	nextEvent() Compute the date of the event, by adding the interval represented by this object to the current date/time.
java.util.Date	nextEvent(java.util.Date lastEventDate) Compute the date of the event, by adding the interval represented by this object to the given date/time.
java.lang.String	toString() Display in a human readable way the frequency represented by this object.

Methods inherited from class java.lang.Object

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

Constructor Detail

EventFrequency

public EventFrequency(java.lang.String interval)

Create a new event frequency.

The frequency string must respect the following syntax:

• 'D' hh mm : daily schedule at hh:mm
• 'W' dd hh mm : weekly schedule at the given day of the week (1:sunday, 2:monday, ..., 7:saturday) at hh:mm
• 'M' dd hh mm : monthly schedule at the given day of the month at hh:mm
• 'h' mm : hourly schedule at the given minute
• 'm' : scheduled every minute (for completness :-))

Where: hh = integer between 0 and 23, mm = integer between 0 and 59, dd (for 'W') = integer between 1 and 7 (1:sunday, 2:monday, ..., 7:saturday), dd (for 'M') = integer between 1 and 31.

Warning: The frequency type is case sensitive! Then you should particularly pay attention at the case when using the frequency types 'M' (monthly) and 'm' (every minute).

Parsing errors are not thrown but "resolved" silently. The "solution" depends of the error. 2 cases of errors are considered:

• Frequency type mismatch: It happens when the first character is not one of the expected (D, W, M, h, m). That means: bad case (i.e. 'd' rather than 'D'), another character. In this case, the frequency will be: daily at 00:00.
• Parameter(s) missing or incorrect: With the "daily" frequency ('D'), at least 2 parameters must be provided ; 3 for "weekly" ('W') and "monthly" ('M') ; only 1 for "hourly" ('h') ; none for "every minute" ('m'). This number of parameters is a minimum: only the n first parameters will be considered while the others will be ignored. If this minimum number of parameters is not respected or if a parameter value is incorrect, all parameters will be set to their default value (which is 0 for all parameter except dd for which it is 1).

Examples:

• "" or NULL = every day at 00:00
• "D 06 30" or "D 6 30" = every day at 06:30
• "D 24 30" = every day at 00:00, because hh must respect the rule: 0 ≤ hh ≤ 23
• "d 06 30" or "T 06 30" = every day at 00:00, because the frequency type "d" (lower case of "D") or "T" do not exist
• "W 2 6 30" = every week on Tuesday at 06:30
• "W 8 06 30" = every week on Sunday at 00:00, because with 'W' dd must respect the rule: 1 ≤ dd ≤ 7
• "M 2 6 30" = every month on the 2nd at 06:30
• "M 32 6 30" = every month on the 1st at 00:00, because with 'M' dd must respect the rule: 1 ≤ dd ≤ 31
• "M 5 6 30 12" = every month on the 5th at 06:30, because at least 3 parameters are expected and so considered: "12" and eventual other parameters are ignored

Parameters:

interval - A string defining the event frequency (see above for the string format).

Method Detail

isTimeElapsed

public boolean isTimeElapsed()

Tell whether the interval between the last event and now is greater or equals to the frequency represented by this object.

Returns:

true if the next event date has been reached, false otherwise.

getNextEvent

public java.util.Date getNextEvent()

Get the date of the next event.

Returns:

Date of the next event, or NULL if no date has yet been computed.

getEventID

public java.lang.String getEventID()

Get a string which identity the period between the last event and the next one (whose the date has been computed by this object).

This ID is built by formatting in string the given date of the last event.

Returns:

ID of the period before the next event.

nextEvent

public java.util.Date nextEvent()

Compute the date of the event, by adding the interval represented by this object to the current date/time.

The role of this function is to compute the next event date, not to get it. After computation, you can get this date thanks to getNextEvent(). Furthermore, using isTimeElapsed() after having called this function will let you test whether the next event should (have) occur(red).

Note: This function computes the next event date by taking the current date as the date of the last event. However, if the last event occurred at a different date, you should use nextEvent(Date).

Returns:

Date at which the next event should occur. (basically, it is: NOW + frequency)

nextEvent

public java.util.Date nextEvent(java.util.Date lastEventDate)

Compute the date of the event, by adding the interval represented by this object to the given date/time.

The role of this function is to compute the next event date, not to get it. After computation, you can get this date thanks to getNextEvent(). Furthermore, using isTimeElapsed() after having called this function will let you test whether the next event should (have) occur(red).

Returns:

Date at which the next event should occur. (basically, it is lastEventDate + frequency)

toString

public java.lang.String toString()

Display in a human readable way the frequency represented by this object.

Overrides:

toString in class java.lang.Object

Returns:

a string, i.e. weekly on Sunday at HH:MM