Re: [threeten-develop] API simplicity; Period

[Roger R. <Rog...@or...>]

Hi Stephen,

On 10/07/2011 06:50 PM, Stephen Colebourne wrote:
> On 7 October 2011 20:11, Roger Riggs<Rog...@or...>  wrote:
...
>> The between() method belongs in LocalDate with the other operations
>> on LocalDates.  It makes more sense there and a matching between()
>> using OffsetDates would be in the OffsetDate class.
>> The between() method would complement the plus(), minus(), and with()
>> operations.
> Thats a poor API. Static factory methods should return the type of the
> class on which they are called in general, or at least a related type.
> You are proposing:
>
>    Period p = LocalDate.between(date1, date2)
>    Period p = LocalDate.daysBetween(date1, date2)
>    Period p = LocalDate.weeksBetween(date1, date2)
>    Period p = LocalDate.monthsBetween(date1, date2)
>    Period p = LocalDate.yearsBetween(date1, date2)
>    ....
>
> which makes no sense to me. It should be clear that the distinguishing
> factor in these methods is the period unit, thus the method should be
> *on* the period unit, where only a single "between" method is needed.
No, I should have more been more concrete, I was proposing a more fluent 
API,
that takes advantage of the instances already available.

      Period p = date1.minus(date2);   // returns the delta, just like 
other arithmetic operators

      Period p = date1.minus(date2).daysOnly();   // If the result 
should only have full days.

Using "of" is not a very fluent usage since it is essentially going back
to creating a new type from primitive types.   It is necessary when creating
objects from primitives and units/types.

Roger