Re: [Numbers] Make "Complex" a "final" class? (Was: [...] API of "Complex")

[Stephen Colebourne]

Some of the classes you are talking about are what I call VALJOs.
Follow these guidelines and your class will be well placed for the
future.
http://blog.joda.org/2014/03/valjos-value-java-objects.html
Stephen

On 2 February 2018 at 12:45, Gilles  wrote:
> On Thu, 1 Feb 2018 08:30:00 -0700, Gary Gregory wrote:
>>
>> Hi All:
>>
>> I like the "of" prefix but I think it might be odd to force the convention
>> for ALL factories. It might be an English language thing for me.
>>
>> For example, (picking a made up example) this reads really well to me:
>> Pair.of(foo, bar) because that what you'd use in spoken English.
>>
>> OTOH, this does not read well to me: Fraction.of(num, denum); this would
>> be
>> better: Fraction.from(num, denum)
>>
>> All of this to say that we should make sure that the factory method "reads
>> well" for that class. I know it might feel subjective.
>>
>> I like the idea of a private ctor but it does not have to be unique in my
>> mind. Sure, it's nice if there is one.
>>
>> I also like the idea of the ctor being private because we can open it up
>> later to protected if we want to allow for subclassing.
>>
>> I would also consider making classes final, especially if the ctor is
>> private.
>
>
> Any caveat on doing that?  Is this a final (!) decision or can one
> change one's mind in a later release?
> What are the benefits?
>
> Thanks,
> Gilles
>
>>
>> Gary
>>
>>
>> On Thu, Feb 1, 2018 at 7:07 AM, Gilles 
>> wrote:
>>
>>> On Thu, 01 Feb 2018 13:59:13 +0100, Gilles wrote:
>>>
 Hi.

 IMHO, there are too many accessor and factory methods.
 We should strive for a lean and consistent API.

 For the factory methods, I suggest the "of" convention:
  public static Complex ofCartesian(double re, double im)
  public static Complex ofPolar(double abs, double arg)
 And, as syntactic sugar:
  public static Complex ofCis(double arg)

>>>
>>> Those are useful too:
>>>public ofReal(double re)
>>>public ofImaginary(double im)
>>>
>>>
 For the accessors:
  public double re() { return real }
  public double im() { return imaginary }

 I'd have
   public double arg()
   public double abs()
 in order to compute the polar coordinates.

 I'm -0 to have others as syntactic sugar since they are
 misleading (a.o. when "implying" the read of a field when
 a computation is performed).

 WDYT?

>>>
>>> In addition to the above, I propose
>>> * to have a single, "private", constructor:
>>> private Complex(double re, double im)
>>> * to remove the "protected" method "createComplex" (
>>>   unless there is a case for inheritance).
>>>
>>> Regards,
>>> Gilles
>
>
>
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[Numbers] Make "Complex" a "final" class? (Was: [...] API of "Complex")

[Gilles]

On Thu, 1 Feb 2018 08:30:00 -0700, Gary Gregory wrote:

Hi All:

I like the "of" prefix but I think it might be odd to force the 
convention

for ALL factories. It might be an English language thing for me.

For example, (picking a made up example) this reads really well to 
me:

Pair.of(foo, bar) because that what you'd use in spoken English.

OTOH, this does not read well to me: Fraction.of(num, denum); this 
would be

better: Fraction.from(num, denum)

All of this to say that we should make sure that the factory method 
"reads

well" for that class. I know it might feel subjective.

I like the idea of a private ctor but it does not have to be unique 
in my

mind. Sure, it's nice if there is one.

I also like the idea of the ctor being private because we can open it 
up

later to protected if we want to allow for subclassing.

I would also consider making classes final, especially if the ctor is
private.


Any caveat on doing that?  Is this a final (!) decision or can one
change one's mind in a later release?
What are the benefits?

Thanks,
Gilles



Gary


On Thu, Feb 1, 2018 at 7:07 AM, Gilles  
wrote:



On Thu, 01 Feb 2018 13:59:13 +0100, Gilles wrote:


Hi.

IMHO, there are too many accessor and factory methods.
We should strive for a lean and consistent API.

For the factory methods, I suggest the "of" convention:
 public static Complex ofCartesian(double re, double im)
 public static Complex ofPolar(double abs, double arg)
And, as syntactic sugar:
 public static Complex ofCis(double arg)



Those are useful too:
   public ofReal(double re)
   public ofImaginary(double im)



For the accessors:
 public double re() { return real }
 public double im() { return imaginary }

I'd have
  public double arg()
  public double abs()
in order to compute the polar coordinates.

I'm -0 to have others as syntactic sugar since they are
misleading (a.o. when "implying" the read of a field when
a computation is performed).

WDYT?



In addition to the above, I propose
* to have a single, "private", constructor:
private Complex(double re, double im)
* to remove the "protected" method "createComplex" (
  unless there is a case for inheritance).

Regards,
Gilles



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