A calendar represents a numeric value that is varying over time.
Calendars can be linked to multiple entities: a maximum capacity limit of a resource, a minimum capacity usage of a resource, a minimum or maximum inventory limit of a buffer, etc…
A calendar has multiple buckets to define the values over time. To determine the calendar value at a certain date the calendar will evaluate each of the buckets and combine the results in the following way:
- A bucket is only valid from its “start” date (inclusive) till its “end” date (exclusive).
Outside of this date range a bucket is never selected. - If multiple bucket are effective on a date, the one with the lowest “priority” value is taken.
In case buckets have the same priority, the value of the bucket with the latest start date is selected. - In case no bucket is effective on a certain date, the calendar will return the “default” value.
Calendar Fields
Field | Type | Description |
name | non-empty string | Name of the calendar. This is the key field and a required attribute. |
default | double | The default value of the calendar when no bucket is effective. |
action | A C AC (default) R |
Type of action to be executed:
|
Method | Description |
setValue([start date],[end date],[value]) | Creates or updates calendar buckets to reflect the specified value in the given date range. |
buckets() | Returns an iterator over the calendar buckets. |
events([start date],[direction]) | Returns an iterator over the calendar events starting from the (optional) start date, either backward or forward in time. These are the dates at which the calendar value is changing. Each event is a tuple with 2 fields:
|
Bucket Fields
Field | Type | Description |
id | integer | Unique identifier within the calendar of the bucket. When left unspecified in the input data it is automatically created. |
start | dateTime | Start date of the validity of this bucket. When left unspecified, the entry is effective from the infinite past. |
end | dateTime | End date of the validity of this bucket. When left unspecified, the entry is effective indefinitely in the future. |
priority | integer | Priority of this bucket when multiple buckets are effective for the same date. Lower values indicate higher priority. |
days | integer between 0 and 127 |
Bit pattern representing the days on which the calendar bucket is valid:
The default value is 127, ie valid on every day of the week. |
starttime | duration | Time when this entry becomes effective on valid days in the valid date horizon. The default value is PT0S, ie midnight |
endtime | duration | Time when this entry becomes ineffective on valid days in the valid date horizon. The default value is PT23H59M59S, ie right before midnight of the next day. |
value | Varies with the calendar type | The actual time-varying value. |
action | A C AC (default) R |
Type of action to be executed:
|
Example XML structures
- Adding or changing a calendar and its buckets
<plan> <calendars> <calendar name="cal"> <default>5</default> <buckets> <bucket start="2007-01-01T00:00:00" value="10" priority="1"/> <!-- This entry overrides the first one during February. --> <bucket start="2007-02-01T00:00:00" end="2007-03-01T00:00:00 value="20" priority="0"/> </buckets> </calendar > </calendars> </plan>
- Removing a calendar
<plan> <calendars> <calendar name="cal" action="R"/> </calendars> </plan>
Example Python code
- Adding or changing a calendar and its buckets
cal = frepple.calendar_double(name="cal", default=5)
- Removing a calendar
frepple.calendar(name="cal", action="R")
- Iterating over all buckets of a calendar
for b in frepple.calendar(name="cal").buckets(): print b.name, b.value
- Iterating over all events of a calendar, going forward in time from a certain date
start = datetime.datetime(2009,1,1) for date, value in frepple.calendar(name="cal").events(start, True): print date, value