NYCPHP Meetup

[Anirudh Zala]

On Wednesday 03 September 2008 06:04:16 Michael B Allen wrote:
> How do people feel about the use of Java-ist "Constants" interfaces like:
>
>   interface Sql_Constants
>   {
>
>       const SELECT = 1;
>       const FROM = 2;
>       const WHERE = 3;
>       const NOT = 4;
>       ....
>
>   }
>
> where the objective is to permit any class that needs these constants
> to access them using "self" like:
>
>   require_once 'Sql/Constants.php';
>
>   class Sql_Parser implements Sql_Constants
>   {
>
>       public function parse($sql)
>       {
>           ...
>           if ($tokenCode === self::WHERE) {

Hello Mike

Defining interface constants, according to me, is not good design pattern even 
if it is enabled later in PHP.

Reason behind this is that Interfaces are primarily designed to define types 
and not to hold data. As well as when any class implements any Interface it 
means it will be implementing all the Methods defined in Interface. This is 
not required in case of Constants that means primary purpose of Interface 
(what is defined in the Interface must be implemented) is not met.

There are certain disadvantages also as mentioned in below thread.

http://www.trap17.com/forums/constant-interface-constant-class-t59974.html

Thanks

Anirudh Zala

>               ...
>
> Mike
> _______________________________________________
> New York PHP Community Talk Mailing List
> http://lists.nyphp.org/mailman/listinfo/talk
>
> NYPHPCon 2006 Presentations Online
> http://www.nyphpcon.com
>
> Show Your Participation in New York PHP
> http://www.nyphp.org/show_participation.php