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static/object method

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Hans Lellelid

22 years ago
Hi all, I have a pattern I'm trying to implement in PHP5 using a class that could be called statically or non-statically. Perhaps "pattern" gives this too much legitimacy :) I can't figure out how to do this & wanted to ask if a) it's possible at all and b) if there's been any solution discussed for such an approach. Here's what I'm trying to do, but can't figure out a way in PHP5 (or a non-hack way in PHP4): - AuthorFinder is a class that can be used statically for default behavior or instantiated if customized behavior is needed. static, default behavior, probably accounts for 80% of uses: $c = new Criteria(Author::NAME, "Leo"); $a = AuthorFinder::find($c); instantiated behavior for performing customizations: $c = new Criteria(Author::NAME, "Leo"); $af = new AuthorFinder(); $af->setLimit(5); $a = $af->find($c); Is there *any* way to accomplish that in PHP5? I can't reference $this -- even to check isset() (which would probably be misleading anyway) from inside a method declared as static. If I do not declare the method static then calling it statically triggers E_STRICT error which I want to avoid since I'm writing PHP5 code. Perhaps I'm missing an obvious solution, in which case I apologize & probably should have asked php-general. It would be *really* cool if PHP could support this type of pattern, as there have been a few cases where I've wanted to apply this in PHP5. Perhaps this has already been discussed & I just didn't notice. Thanks, Hans

Andre Cerqueira

22 years ago
Hi I think it should be constructor's job to set up an instance with the defaults. (no need for static in this case) Am i missing something? Hans Lellelid wrote:

Hans Lellelid

22 years ago
Andre Cerqueira wrote:
>> >> $c = new Criteria(Author::NAME, "Leo"); >> $a = AuthorFinder::find($c); >> >> instantiated behavior for performing customizations: >> >> $c = new Criteria(Author::NAME, "Leo"); >> $af = new AuthorFinder(); >> $af->setLimit(5); >> $a = $af->find($c); >> > I think it should be constructor's job to set up an instance with the > defaults. (no need for static in this case) > Am i missing something? > > static, default behavior, probably accounts for 80% of uses:
Well, kinda, yeah. The other part of the equation is that this class is generated, which is what allows it to be static. The default values for things are built into the class as static properties or class constants or whatever. The idea is that most of the time this class is really a static class, which needs no object instance to perform 'find' functions. Of course, you're right, using it non-statically only is a solution, but it would be far more elegant (IMO) if that weren't necessary :) Cheers, Hans

Andre Cerqueira

22 years ago
Sorry, I probably underestimated the question I just thought it would make things simple I'm still learning that OO stuff hehe, thought static would set the scope to class instead of object for find. That way you would have to pass the object as a parameter to the static find, so that it would get access to object data (since find is from the class, not the object). And that didn't seem like an elegant way eighter hehe Probably there are other ways... I should have waited for other replies, shut up and read hehe, but i fail that from time to time... Hans Lellelid wrote:

Taco van den Broek

22 years ago
Hans Lellelid wrote:
> Hi all, > > I have a pattern I'm trying to implement in PHP5 using a class that > could be called statically or non-statically. Perhaps "pattern" gives > this too much legitimacy :) I can't figure out how to do this & wanted > to ask if a) it's possible at all and b) if there's been any solution > discussed for such an approach. > > Here's what I'm trying to do, but can't figure out a way in PHP5 (or a > non-hack way in PHP4): > > - AuthorFinder is a class that can be used statically for default > behavior or instantiated if customized behavior is needed. > > static, default behavior, probably accounts for 80% of uses: > > $c = new Criteria(Author::NAME, "Leo"); > $a = AuthorFinder::find($c);
You pass your criteria to your search class as instantiated objects, why don't you pass your parameters/config flags as another type of object? Maybe like this: $c = new Criteria(Author::NAME, "Leo"); $f = new ConfigFlag(AuthorFinder::LIMIT, '5'); $a = AuthorFinder::find($c, $f); You could then check the $f object for any customizations, just like you check the $c object for where to search.

Alan Knowles

22 years ago
the E_STRICT warnings on static calls to non static methods are probably usefull, (as $this could be defined totally randomly), so it does make some sense.. btw: does that mean: class a { function find() { } } class b extends a { function find() { } } // call the toplevel parent method.. (skip the imediate parent) class c extends b { function find() { a::find() } } $a = new c; $c->find(); illicits and E_STRICT warning??? (sorry I havent got the latest PHP5 compiled ATM..) Regards Alan Taco van den Broek wrote:
> Hans Lellelid wrote: > >> Hi all, >> >> I have a pattern I'm trying to implement in PHP5 using a class that >> could be called statically or non-statically. Perhaps "pattern" gives >> this too much legitimacy :) I can't figure out how to do this & >> wanted to ask if a) it's possible at all and b) if there's been any >> solution discussed for such an approach. >> >> Here's what I'm trying to do, but can't figure out a way in PHP5 (or a >> non-hack way in PHP4): >> >> - AuthorFinder is a class that can be used statically for default >> behavior or instantiated if customized behavior is needed. >> >> static, default behavior, probably accounts for 80% of uses: >> >> $c = new Criteria(Author::NAME, "Leo"); >> $a = AuthorFinder::find($c); > > > You pass your criteria to your search class as instantiated objects, why > don't you pass your parameters/config flags as another type of object? > Maybe like this: > > $c = new Criteria(Author::NAME, "Leo"); > $f = new ConfigFlag(AuthorFinder::LIMIT, '5'); > $a = AuthorFinder::find($c, $f); > > You could then check the $f object for any customizations, just like you > check the $c object for where to search. > >> >> instantiated behavior for performing customizations: >> >> $c = new Criteria(Author::NAME, "Leo"); >> $af = new AuthorFinder(); >> $af->setLimit(5); >> $a = $af->find($c); >> >> Is there *any* way to accomplish that in PHP5? I can't reference >> $this -- even to check isset() (which would probably be misleading >> anyway) from inside a method declared as static. If I do not declare >> the method static then calling it statically triggers E_STRICT error >> which I want to avoid since I'm writing PHP5 code. Perhaps I'm >> missing an obvious solution, in which case I apologize & probably >> should have asked php-general. >> >> It would be *really* cool if PHP could support this type of pattern, >> as there have been a few cases where I've wanted to apply this in >> PHP5. Perhaps this has already been discussed & I just didn't notice. >> >> Thanks, >> Hans > >
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Hans Lellelid

22 years ago
Alan Knowles wrote:
> the E_STRICT warnings on static calls to non static methods are probably > usefull, (as $this could be defined totally randomly), so it does make > some sense.. > > btw: does that mean: > > class a { function find() { } } > class b extends a { function find() { } } > > // call the toplevel parent method.. (skip the imediate parent) > class c extends b { function find() { a::find() } } > $a = new c; > $c->find(); > > illicits and E_STRICT warning???
Hmm --yes unless you declare a::find() as a 'static' method. The good news is that static methods can be used on objects w/ no errors (so you can definitely accomplish that design, but would just have to declare methods as 'static'). So, basically: - if you try to call a "normal" method statically you will get E_STRICT notice - if you make any reference to $this in a 'static' method you will get E_FATAL error (Correct me if I'm missing anything) Hans

Hans Lellelid

22 years ago
Taco Van Den Broek wrote:
> Hans Lellelid wrote: >> static, default behavior, probably accounts for 80% of uses: >> >> $c = new Criteria(Author::NAME, "Leo"); >> $a = AuthorFinder::find($c); > > > You pass your criteria to your search class as instantiated objects, why > don't you pass your parameters/config flags as another type of object? > Maybe like this: > > $c = new Criteria(Author::NAME, "Leo"); > $f = new ConfigFlag(AuthorFinder::LIMIT, '5'); > $a = AuthorFinder::find($c, $f); > > You could then check the $f object for any customizations, just like you > check the $c object for where to search.
That's a good suggestion -- probably the cleanest design possible in current PHP object model. Thanks, Hans