Fair enough.
Initially I suggested using a temporal expression plus duration to solve
the problem. You said there will be errors during DST transitions -
that's true. Then I said you would need a start temporal expression and
an end temporal expression. But I realized this would be too much work
for the end user because it would be too complicated. So I suggested
using temporal expression with duration, plus check for a DST transition
using the TimeZone object. This would be the quickest way to get it
implemented, but it's a bad long term strategy because it doesn't
consider other billing scenarios. So I started sketching out some code
that would handle arbitrarily complex billing scenarios and gave you
what I had so far, in case you were interested.
To summarize: since you're pressed for time, the temporal expression
plus duration plus DST check would be your best choice. The code I
sketched out doesn't have the DST check because the ending day and time
is specified - instead of using a duration. In the meantime I'm working
on the "ideal" version - because I will need it for the project I'm
working on.
Sorry for the confusion.
-Adrian
On 2/1/2011 5:05 PM, Scott Gray wrote:
Each object executes a loop that tests to see if the date falls within its range
Isn't this exactly what job temporal expressions are intended for? Twice now you've told
me that something isn't suitable (TimeOfDayRange and temporal expressions themselves) but
without making any effort to explain why, if I have a hammer and something that looks
like a nail then simply saying "that isn't a nail" isn't going to convince me.
I need you to tell me that the nail is actually made of rubber and hitting it will just
smash my thumb :-)
Regards
Scott
On 2/02/2011, at 9:24 AM, [email protected] wrote:
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
