Re: What is the practical use of "abstract" and "interface"?

Daevid Vincent wrote: > I've had at least three job interviews in the past two weeks, and each one has asked me > this rather "text book academic" question regarding the difference between > "abstract" vs. "interface". I've been coding for nearly 20 years, and at > least 10 of those have been in PHP and another 3 in J++. I have NEVER used either of these > concepts/keywords? Am I missing some exciting tool/feature? > > All the reading I've done tonight just reinforces my thoughts that these are, for the most > part useless. Unless you're building some HUGE project that has an API and there are teams of > people that are going to extend your framework, then what good are they? > > This DB wrapper is the closest to an answer I've come across. > > http://www.developer.com/lang/php/article.php/3604111 > > But that still doesn't explain the difference between abstract and interface, it only > illustrates the possible need for a 'template' so others know which methods they must > implement. In my mind, it just seems like overhead, as if you were going to write another DB wrapper > using this one, then wouldn't you just look at their code (example) and implement those same > methods anyways? I mean, you'd have to look at the abstract/interface to find out the required > methods, so why not skip that and just look at the actual class instead? > > Here are two more pages that still don't seem to answer why there are both and when > you'd use one over the other? > > > http://www.hiteshagrawal.com/php/oops-in-php5/oops-in-php5-tutorial-abstract-class > > http://www.hiteshagrawal.com/php/oops-in-php5/oops-in-php5-using-interface > > And then this completely absurd over the top use of them for a HelloWorld example, which seems > to use them just for the sake of using them... > > http://marc.info/?l=php-general&m=115950654928311&w=2 > > Lastly was this page: > > > http://www.phpro.org/tutorials/Object-Oriented-Programming-with-PHP.html > > Which seems to only really provide a "hack" (printerFax) to circumvent the lack of > multiple inheritance. > > > Can someone clear this up for me? Look at this url: http://www.codeproject.com/KB/cs/abstractsvsinterfaces.aspx Iñigo > Daevid. > http://daevid.com > > -- -------- Iñigo Medina García Librería Díaz de Santos Madrid (Spain) imedina@diazdesantos.es facilmejor@gmail.com