Btw, the reason the TimeOfDay range didn't work was because of the
next() method. If the expression includes a minute component and an hour
component, what is being incremented when next() is called? It ended up
being ambiguous and unreliable.
-Adrian
On 2/1/2011 10:22 PM, Adrian Crum wrote:
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
