Re: [PHP] Singleton with variable parameters

[Nathan Nobbe]

On Wed, Dec 15, 2010 at 2:11 PM, Sebastian Detert php-maill...@elygor.dewrote:

 Hi guys,

 I am trying to generate an abstract Singleton class for use in arbitrary
 classes, like

 class Foo extends Singleton {}

 and generate a new class with Foo - getInstance();


Until traits release I think you'll find this painful as any class that
extends Singleton must now have extra functionality imbued via interfaces
and composition.

You will probly prefer to use a registry, something like
Registry::getInstance('classname', array('parameters'));

Even if you go with an abstract base class you will want an array of
instances internally.

How can I manage to use this with an unkown number of parameters like Foo -
 getInstance('a', 'b'); ?


yes, func_get_args()  call_user_func_array() however, fyi, these are very
slow.


 Something like self::$instance = call_user_func (array(static ,
 __construct), func_get_args()); instead of self::$instance = new self;
 doesn't work and an eval() is too slow.


if performance is a concern why not use setters to establish state on all of
your classes and keep the getInstance method down to 0 params.  As long as
your singletons aren't immutable this should work just fine.

-nathan

RE: [PHP] Singleton with variable parameters

[Tommy Pham]

 -Original Message-
 From: Nathan Nobbe [mailto:quickshif...@gmail.com]
 Sent: Wednesday, December 15, 2010 1:31 PM
 To: Sebastian Detert
 Cc: php-general@lists.php.net
 Subject: Re: [PHP] Singleton with variable parameters
 
 On Wed, Dec 15, 2010 at 2:11 PM, Sebastian Detert php-
 maill...@elygor.dewrote:
 
  Hi guys,
 
  I am trying to generate an abstract Singleton class for use in
  arbitrary classes, like
 
  class Foo extends Singleton {}
 
  and generate a new class with Foo - getInstance();
 
 
 Until traits release I think you'll find this painful as any class that 
 extends
 Singleton must now have extra functionality imbued via interfaces and
 composition.
 
 You will probly prefer to use a registry, something like
 Registry::getInstance('classname', array('parameters'));
 
 Even if you go with an abstract base class you will want an array of instances
 internally.
 
 How can I manage to use this with an unkown number of parameters like
 Foo -
  getInstance('a', 'b'); ?
 
 
 yes, func_get_args()  call_user_func_array() however, fyi, these are very
 slow.
 
 
  Something like self::$instance = call_user_func (array(static ,
  __construct), func_get_args()); instead of self::$instance = new self;
  doesn't work and an eval() is too slow.
 
 
 if performance is a concern why not use setters to establish state on all of
 your classes and keep the getInstance method down to 0 params.  As long as
 your singletons aren't immutable this should work just fine.
 
 -nathan

Sebastian,

If you need to have some way to keep track of all the instances of subclasses 
and be able to communicate between them, then you'll have need to have the 
self::$instances = array() in the base class, as Nathan mentioned.  But 
implementing instance map in the base abstract is unnecessary, IMO, as it could 
get very messy in the long run.  I suggest you look into Interfaces.  It will 
help make your code easier to manage in the future as your app gets more 
sophisticated.

Regards,
Tommy


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