Actually, temporal expressions should not be used because they aren't
the right tool for the job. Here is what I sketched out initially, you
can use it if you want:
We need a data structure that includes a starting day of week and
time, an ending day of week and time, a billing rate, and a billing
increment. The structure also has a single method to compute billing.
The structures are assembled in chronological order in a chain or array.
A second structure is used as an argument for the first structure's
billing method. It includes Dates representing the start and end of
the billing period, an accumulator for the billed amount, and an
optional List to keep track of the various rates and quantities that
were used to compute the total.
This second structure is initialized and passed to the first object in
the chain or is passed to each object in the array. Each object
executes a loop that tests to see if the date falls within its range,
and if it does, money is added to the accumulator. The billing period
start date is incremented by the increment amount and the loop
repeats. When the date falls outside the object's range, control is
passed to the next object in the array/chain. When the billing period
start date equals the billing period end date, the process stops.
-Adrian
Quoting Scott Gray <[email protected]>:
Hi Adrian,
The reasons you've mentioned below for why temporal expressions
shouldn't be used simply don't apply to my situation. All I have to
support is an admin defining the rate windows for a tiny date range
(maybe 3-10 days) and then apply pricing based on what windows a
start time + duration fall into. Aside from making sure the
appropriate timezone is applied and nothing quirky happens around
DST, I have no other additional complexities in my requirements.
I would love to be able to collaborate with you on a more robust
implementation but I simply don't have the time, unfortunately I
only have hours available to design and implement a solution rather
than days or weeks. Thanks for sharing your thoughts though, I
really appreciate it.
Regards
Scott
On 2/02/2011, at 6:15 AM, [email protected] wrote:
Scott,
I don't think temporal expressions alone will do the job. Here's why:
The type of billing you describe is what we call in the US a "shift
differential." There are other factors that can affect billing too,
like billing overtime if an employee works more than 8 hours in one
day or 40 hours in one week. In addition, you might want to bill
overtime for an employee who works on a holiday.
These same rules could be applied to payroll to generate time sheets.
I'm thinking we need something more comprehensive and flexible than
what you described.
I have experience in writing software for these types of scenarios.
If you are interested in collaborating on a design, I would be
happy to help. If so, let's open a Jira issue and start sharing
ideas.
-Adrian
Quoting Adrian Crum <[email protected]>:
I'm still scratching my head on this one. I will need a similar
implementation in the near future, so I'm interested in helping
with the design. I'm reading Fowler's Analysis Patterns (7.7) to
see what his solution is.
-Adrian
On 2/1/2011 2:09 AM, Scott Gray wrote:
It's all a little bit complicated and I keep wondering to myself
why I don't just implement a TimeOfDayRange** to get me past it.
Basically worker time is orderable in 15 minute increments with a
start time and a duration and I then have to break that duration
down into the relevant rates. I was hoping to just be able to
iterate over each ordered 15 minute intervals and test them
against each of the 3 temporal expressions (standard, overtime,
double time) to determine which window each falls within.
I can't seem to understand why DateRange, HourRange and
MinuteRange are okay but a TimeOfDayRange is a bad design?
** I just noticed the deprecated implementation in 10.04, and it
seems to do exactly what I had in mind, even if the
design/implementation is flawed do you think it might work for my
situation?
Thanks
Scott
On 1/02/2011, at 7:25 PM, Adrian Crum wrote:
Thinking about this more...
It might be easier to leverage the existing temporal expression
+ time duration code, and simply perform a check to see if a DST
transition occurred during the billing period. You can perform
that check by using the TimeZone object.
-Adrian
On 1/31/2011 11:05 AM, [email protected] wrote:
That is an interesting problem to solve. At first glance it
seems you would need separate event start and event end
expressions.
-Adrian
Quoting Scott Gray<[email protected]>:
Thanks Adrian, I had a feeling that would be the case but just
wanted to double check.
What I am trying to do is model different ranges of time in
which a customer would get charged a given rate (standard,
overtime, double time). The only concern I have with using a
rate start time and duration is daylight saving, if a window
were to begin at midnight and end at 8.30am then using an
8.5hr duration wouldn't work correctly when daylight savings
starts and ends. So for me it's less important how long a
window lasts but rather at what specific time it closes.
Thanks
Scott
HotWax Media
http://www.hotwaxmedia.com
On 1/02/2011, at 3:03 AM, Adrian Crum wrote:
Scott,
The TimeOfDay range expression was a bad design and it didn't
work, so it was replaced with MinuteRange and HourRange.
It looks like you might be trying to combine a temporal
expression with a duration. Does the event keep repeating
from 05:00 to 08:30? Or does it occur at 05:00 and have a
duration of 3.5 hours? Keep in mind the Temporal Expression
indicates when an event occurs, not how long it lasts.
-Adrian
On 1/30/2011 6:47 PM, Scott Gray wrote:
Hi Adrian (I assume you're the only one that knows...),
In the original jira issue for the temporal expression
implementation there was mention of a TimeOfDayRange
expression (http://markmail.org/message/pz2i3kzavcnee4ca)
but I can't seem to find a corresponding class in the trunk?
I'm looking to model something along the lines of:
Intersection:
DayOfWeekRange(Monday, Friday)
Union:
TimeOfDayRange(5:00, 08:30)
TimeOfDayRange(17:30, 22:30)
At the moment the only way I can see to do this is with
something quite complex like:
Intersection:
DayOfWeekRange(Monday, Friday)
Union:
Union:
HourOfDayRange(5:00, 08:00)
Intersection:
HourOfDayRange(08:00, 08:00)
MinuteOfDyRange(0, 30)
Union:
Intersection:
HourOfDayRange(17:00, 17:00)
MinuteOfDyRange(30, 59)
HourOfDayRange(18:00, 22:00)
Intersection:
HourOfDayRange(22:00, 22:00)
MinuteOfDyRange(0, 30)
Assuming the above is even correct, is it my only option in
the current implementation?
Thanks
Scott
HotWax Media
http://www.hotwaxmedia.com
