Re: [PHP] [PHP5] Super constructor?

[Justin Patrin]

Hmm, looks like my reply got lost. Here's my ideas:
Instead of parent::__construct() use Class1::__construc(). This way, you 
go straight to the top-level constructor without going through the 
middle constructors. This means that you *must* overload __construct in 
all child classes or else the constructor of the immediate parent will 
be called.

If you want to leave the option of no child constructor open, you could 
use something like:

parent::__construct();
if(strtolower(get_class($this)) == 'class2') {
  //do constructor things for class2
}
in the constructor for Class2. Then if Class3 has no constructor, the 
Class2 constructor code won't be run.

Frzzman wrote:
Yeah you understood me, thanks god :D but not fully :(
But the problem is right in your code (sorry :D)
What if I create an instance of ChildClass, its constructor won't be 
called (since it commented out), but if I un-comment its constructor, it 
will be called even if I create an instance of GrandChildClass?

Let me make some simple diagram ;)
Class1 <-- Class2 <-- Class3 <-- Class4
If I create an instance of Class4, then Class4's constructor and 
Class1's constructor must be called, neither Class3 nor Class2.

You can see that Class1's constructor will always be called, and the 
constructor of the lowest class in the class tree will be called.

I think this is a bit complex, I can define a final function in Class1, 
and call it in every deriver class constructor, it will solve the 
problem (I think) but it's not convenience, I want it done automatically...

Any idea are welcome :D
Chris wrote:
FrzzMan wrote:
Hi guys, hey don't laugh at the subject, in fact I don't what to call 
it, so let's call it super constructor :D

Let's see following code...
class Base
{
    __construct()
    {
        // Do something
    }
}
class One extends Base
{
    __construct()
    {
        // Do nothing
    }
}
class OneMore extends One
{
    __construct()
    {
        // Do things :D
    }
}
So when I create an instance of OneMore class by:
$OneMoreInstance = new OneMore()
The __construct() method of class OneMore will be called, not the one 
of One and Base, right?

So is there any way around to make the Base class have a contructor 
that will be called everytime one of its child initialize?

My problem, I want all of the classes in my object are extend from 
one base class, so they are all have some common properties and 
function, but PHP won't implicit call the contructor (that's the 
right way)... btw, in my case, this is bad, as bad as every 
constructor would be called...

Well, hope you understand what I'm trying to say...
I'm not positive I understand you correctly, but I think this will 
answer your question.

Example Classes:
class ParentClass
{
   function __construct()
   {
       echo 'ParentClass::__construct()',"\r\n";
   }
}
class ChildClass extends ParentClass
{
/*
   function __construct()
   {
       parent::__construct();
       echo 'ChildClass::__construct()',"\r\n";
   }
//*/
}
class GrandChildClass extends ChildClass
{
   function __construct()
   {
       parent::__construct();
       echo 'GrandChildClass::__construct()',"\r\n";
   }
}
__construct is just like any other method, if you overload it 
(redefine it in a child class), the parent method will not be called 
automatically, so, if you want the functionality of both, you can call 
the parent constructor from the childs constructor. If the direct 
parent doesn't have a constructor, the next parent's constructor is 
checked and so on.

In the above example when defining a GrandChildClass, its constructor 
and the ParentClass::__construct() are will both run. If you uncomment 
ChildClass::__construct(), it will run as well.

--
paperCrane <Justin Patrin>
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