[RESOLVED] Object Interaction

JakeWarner


class ClassExample1 {
 var $bleh='test';

 function __construct() {
   $Class2->randFunc();
 }


}

class ClassExample2 {

 function randFunc() {
  global $Class1;
   if($Class1->bleh=='test') {
     echo 'moo';
   }


 }


}

$Class2 = new ClassExample2();
$Class1 = new ClassExample1();

Why wouldn't this work? I have an idea, but yeah...

NogDog

I'm not 100% how to answer this since to some extent it depends on what you are trying to accomplish (and the example code is obviously very abstract). In general though, "global" is not a good thing as it causes troublesome "close-coupling" between the function and the application, and it's even more frowned upon in OOP where "encapsulation" is a primary concept.

Depending on the actual functionality you need, you will either need to pass instantiated objects to the class's constructors and/or instantiate objects from within the classes.

JakeWarner

Well I'm working on a platform right now where I have

$Globals->GetCoreGlobals(); (which connects to the database and gets the globals) but instead of saving the globals in something like $Globals->CoreGlobals; I want to save them as $Platform->CoreGlobals (so that I only have to global $Platform) in every other function.

Do you think I should have $CoreGlobals be an array outside of any class? 🙁

laserlight

JakeWarner wrote:
$Globals->GetCoreGlobals(); (which connects to the database and gets the globals) but instead of saving the globals in something like $Globals->CoreGlobals; I want to save them as $Platform->CoreGlobals (so that I only have to global $Platform) in every other function.

It seems to me that the difference between $Globals->CoreGlobals and $Platform->CoreGlobals is merely in the name. How else do they differ?

JakeWarner wrote:
Do you think I should have $CoreGlobals be an array outside of any class?

It sounds like $CoreGlobals should be a singleton, so perhaps the singleton pattern would be appropriate.

JakeWarner

Can you explain about the 'singleton pattern'?

And the $Platform class will have other variables too; it will be the "main class". All of the globals needed by other modules will be accessing it. The $Globals module just deals specificly with $POST, $GET, and the globals from the database.

laserlight

JakeWarner wrote:
Can you explain about the 'singleton pattern'?

You might want to search the Web for "singleton pattern" and "PHP singleton". There are articles that can explain the concept, with examples, and discussion on their use and abuse, better than a forum post can.

The basic idea is to allow just one instance of a global object and provide an interface such that there is a single point of access to it. Consequently, you would not be declaring the global object as global within function scope, but merely use the interface to access the global object directly. If the global object is not yet created at that point, the interface's implementation would create it transparently to the caller.

NogDog

Of course, before you get too carried away with singleton's, you might also want to do a web search on "why singletons are bad". (I'm not saying to never use a singleton pattern, just be sure you understand the trade-offs if/when you do.)

laserlight

NogDog wrote:
Of course, before you get too carried away with singleton's, you might also want to do a web search on "why singletons are bad".

I would note that those are problems associated with global variables and global state rather than with singletons per se.

JakeWarner

So, if I made $Platform a singleton, would I be able to access $Platform and it's variables from inside of any other class?

laserlight

JakeWarner wrote:
So, if I made $Platform a singleton, would I be able to access $Platform and it's variables from inside of any other class?

Yes, assuming that the file containing the class definition is included correctly.

That said, are you sure that you need so many global variables? It would be better to only process those global variables that are specifically needed.

JakeWarner

$Platform is now a singleton, how do I access the vars of $Platform in $Globals?

I tried to add "global $Platform" in $Globals->GetCoreGlobals();

laserlight

JakeWarner wrote:
$Platform is now a singleton, how do I access the vars of $Platform in $Globals?

If you already have a singleton, why do you need $Globals?

JakeWarner wrote:
I tried to add "global $Platform" in $Globals->GetCoreGlobals();

You would access Platform::getInstance() in $Globals->GetCoreGlobals().

JakeWarner

I'm going to just store the globals in the globals class I suppose.

Ok, another quick question.

$Modules['Core']['Globals'] = new Globals();
$Modules['Core']['Platform'] = new Platform();

I want to create a "shortcut" so that $Platform = $Modules['Core']['Platform']. Would I just do

$Platform = $Modules['Core']['Platform'];

or would I have to setup some type of pointer or something.

laserlight

JakeWarner wrote:
I'm going to just store the globals in the globals class I suppose.

I thought you wanted to store them in the Platform class.

JakeWarner wrote:
I want to create a "shortcut" so that $Platform = $Modules['Core']['Platform'].

In that case $Platform is not a singleton (but that is okay).

JakeWarner wrote:
or would I have to setup some type of pointer or something.

Class objects are implicitly pointers.

JakeWarner

Since $Modules['Core']['Platform'] is a class; I can do $Platform = $Modules['Core']['Platform']; without creating a new instance of it?

laserlight

JakeWarner wrote:
Since $Modules['Core']['Platform'] is a class

It is not a class; it is an object.

JakeWarner wrote:
I can do $Platform = $Modules['Core']['Platform']; without creating a new instance of it?

Yes.

JakeWarner

thank you 🙂