DWT2

[Jacob Carlborg]

On 2011-04-11 14:20, Steven Schveighoffer wrote:
> On Sun, 10 Apr 2011 07:09:52 -0400, Jacob Carlborg <doob at me.com> wrote:
>
>> On 2011-04-08 16:45, Steven Schveighoffer wrote:
>>> On Fri, 08 Apr 2011 10:36:39 -0400, Andrej Mitrovic
>>> <andrej.mitrovich at gmail.com> wrote:
>>>
>>>> On 4/8/11, Bruno Medeiros <brunodomedeiros+spam at com.gmail> wrote:
>>>>> On 05/04/2011 04:54, Andrej Mitrovic wrote:
>>>>>> You have to be kidding me. Who writes code like this?
>>>>>>
>>>>>> http://i.imgur.com/BBQde.png
>>>>>
>>>>> What's wrong with it? Do you mean the anonymous classes with all the
>>>>> fields and contructors for passing the variables in the enclosing
>>>>> scope?
>>>>>
>>>>> --
>>>>> Bruno Medeiros - Software Engineer
>>>>>
>>>>
>>>> I don't understand the need to create huge anonymous classes. If
>>>> you're going to create or override so many methods, you might as well
>>>> create a new class instead of embedding one in the call.
>>>>
>>>> Maybe that's a standard way of doing it in Java, but I'd never code
>>>> like this. Maybe it's because I don't depend on an IDE, and like to
>>>> keep my code clean. I'm not a fan of deeply nested code.
>>>
>>> I think the reason it looks like this is because Java does not have
>>> delegates. Anonymous delegates are much easier to read, and also do not
>>> take up heap space.
>>>
>>> If anything, I'd say a very worthwhile project would be to change all
>>> the callback interfaces and anonymous classes to delegates.
>>>
>>> -Steve
>>
>> DWT already have a way to pass a delegate to a function expecting an
>> interface. It will create a class the implements the interface and
>> then delegate the call to, in this case "handleEvent", to the
>> delegate. Have a look at the bottom of:
>> http://dsource.org/projects/dwt/wiki/DiffToOriginal
>>
>
> I meant it should be redesigned so the delegate is the only way. It
> seems to me like the reason for using anonymous classes for callbacks is
> because Java did not have delegates.

Ok, I see. Yes Java uses anonymous classes because it doesn't have 
delegates.

> I'd replace any requirements for certain interfaces with a requirement
> for a delegate. Delegates are cheap to pass around (no heap allocation
> required), and easier to create in D than anonymous classes.
>
> It's a one-for-one swap when an interface in DWT just has one function,
> and ones that have multiple functions could probably be either
> redesigned into multiple delegates, or use template functions to extract
> delegates.
>
> -Steve

I'll have to think about this.

-- 
/Jacob Carlborg