Multi-Classes and "extends"

[Webase]

Hello! I need some help with classes.
I have 3 functions files, I want all of then to share their information, I'm using a class.
functions.php - class UNDERIO
functions-city.php - class CITY extends UNDERIO
integrate/ipbsdk_class.inc.php - class IPBSDK extends UNDERIO

They are all "require_once" on that order...
When I do $UR =& new IPBSDK();
Only the functions from functions.php and integrate/ipbsdk_class.inc.php are gotten, how can I make the ones from CITY come too?

Thanks!

[thorpe]

Make IPBSDK extend CITY. However, are you sure they really should extends each other? Do they even have anything in common?

Just because one class requires functionality available within another class does not always meen it should extend it.

[Webase]

Oh... well, then how could I do it?
I just want the classes to share their info... like the login function is on one, the other one I want is on another. But I want to be able to check if it's logged in inside the function...

Like this

On functions-city.php
function add_job(stuff) {
if ($this->logged_in()) {

}
}

But logged_in() is on another function file...
So how do I do this?
Thanks a lot!

[Drakla]

Depending on your classes it might be good to stick to the old "Favour composition over Inheritance" which basically says if a class does its own thing and that's useful in another class then sometimes it's best to have it as a member property than extending it. I've got an email tagging class that I eventually split into a tagger class and an email template class. Subsequently it was much easier to maintain.

I've thrown this article at somebody already recently, but taken a look.

http://devzone.zend.com/node/view/id/4

[Webase]

I didn't understand much from that article is there any else where I can learn or some example you guys can give me?

Thanks...

[jdorsch]

// This is bad becuase Jobs really isn't a login, you are inheriting from an object
// that has totally unrelated functionality.  Its like having a class for HouseCat and // making it extend Microwave
class Login
{
   public function logged_in() {...}
}


class Jobs extends Login
{
   public function add_job()
  {
     if( $this->logged_in ) .....
  }
}


// Better
class Jobs
{
   private loginObj ;

   public function __construct()
   {
      $this->loginObj = new Login() ;
   }

  public function add_job()
  {
     $this->loginObj->logged_in() ;
  }
}

// If you only want to have one login object and have it shared across alll your classes


// This is ok if login has to be instantiated
class Jobs
{
   public function __construct( Login $login )
  {
      $this->loginObj = new Login() ;
  }
}

// This is even better if you can make login be a static class
class Jobs
{
  public function addJob()
  {
     Login::logged_in() ;
  }
}

// or make login a singleton and have it instantiate an private
// singleton instance of itself
class Jobs
{
  public function addJob()
  {
     Login::getObj()->loggedin_in() ;
  }
}