Provide a protocol for date-range limited day-count calculations.
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Namespaces |
namespace | bbldc |
Detailed Description
- Outline
-
-
- Purpose:
- Provide a protocol for date-range limited day-count calculations.
-
- Classes:
-
- See also:
- Component bbldc_basicdaterangedaycountadapter, Component bbldc_perioddaterangedaycountadapter
-
- Description:
- This component provides a protocol,
bbldc::DateRangeDayCount
, for implementing an arbitrary day-count convention. Concrete implementations of this protocol may implement, say, the BUS-252 day-count convention, or a custom day-count convention appropriate for some niche market.
- Several of the components in
bbldc
provide individual day-count convention support through interfaces that are functionally identical to the abstract interface provided by this component, except that they do not inherit from bbldc::DateRangeDayCount
. In conjunction with the adapter components (e.g., bbldc_basicdaterangedaycountadapter
), bbldc::DateRangeDayCount
is intended to allow run-time binding of these and other similar day-count implementations.
- This protocol requires two methods,
firstDate
and lastDate
, that define a date range for which calculations are valid, to reflect the valid range of, say, a calendar required for the computations.
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- Usage:
- This section illustrates intended use of this component.
-
- Example 1: Definition and Use of a Concrete Day-Count Convention:
- This example shows the definition and use of a simple concrete day-count convention. This functionality suffices to demonstrate the requisite steps for having a working day-count convention:
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Define a concrete day-count type derived from
bbldc::DateRangeDayCount
.
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Implement the four pure virtual methods.
-
Instantiate and use an object of the concrete type.
- First, define the (derived)
my_DayCountConvention
class and implement its constructor inline (for convenience, directly within the derived-class definition):
class my_DayCountConvention : public bbldc::DateRangeDayCount {
bdlt::Date d_firstDate;
bdlt::Date d_lastDate;
public:
my_DayCountConvention()
: d_firstDate(1, 1, 1), d_lastDate(9999, 12, 31) { }
virtual ~my_DayCountConvention();
virtual int daysDiff(const bdlt::Date& beginDate,
const bdlt::Date& endDate) const;
virtual const bdlt::Date& firstDate() const;
virtual const bdlt::Date& lastDate() const;
virtual double yearsDiff(const bdlt::Date& beginDate,
const bdlt::Date& endDate) const;
};
Then, implement the destructor. Note, however, that we always implement a virtual destructor (non-inline) in the .cpp file (to indicate the unique location of the class's virtual table):
my_DayCountConvention::~my_DayCountConvention() { }
Next, we implement the (virtual) daysDiff
, firstDate
, lastDate
, and yearsDiff
methods, which incorporate the "policy" of what it means for this day-count convention to calculate day count, year fraction, and the valid range of the convention instance: int my_DayCountConvention::daysDiff(const bdlt::Date& beginDate,
const bdlt::Date& endDate) const
{
return endDate - beginDate;
}
const bdlt::Date& my_DayCountConvention::firstDate() const
{
return d_firstDate;
}
const bdlt::Date& my_DayCountConvention::lastDate() const
{
return d_lastDate;
}
double my_DayCountConvention::yearsDiff(const bdlt::Date& beginDate,
const bdlt::Date& endDate) const
{
return static_cast<double>(endDate - beginDate) / 365.0;
}
Then, create two bdlt::Date
variables, d1
and d2
, to use with the my_DayCountConvention
object and its day-count convention methods: Next, we obtain a bbldc::DateRangeDayCount
reference from an instantiated my_DayCountConvention
: Now, we compute the day count between the two dates: const int daysDiff = dcc.daysDiff(d1, d2);
assert(73 == daysDiff);
Finally, we compute the year fraction between the two dates: const double yearsDiff = dcc.yearsDiff(d1, d2);
assert(0.1999 < yearsDiff && 0.2001 > yearsDiff);