about parent members

[Liquid Fire]

I know that php classes are not exactly the same as other languages classes(like C++) so i have a question.  Let say i have this code:

<?php
class a
{
    protected function test()
    {
        print_r($this->_data_map);
    }
    
    protected $_data_map;
}

class b extends a
{
    public function __contruct()
    {
        parent::$_data_map = array("a" => "b");
    }
    
    public function test()
    {
        parent::test();
    }
}

$a = new a();
$b = new b();

$b->test();
?>

My question is will class a have access to the data created by class b's constructor?

[keeB]

OK, I figured it out.

 

First..

 

    public function __contruct()

 

Should be

 

    public function __construct()

 

That was annoying! I usually use the name of the class for the constructor. In this case, it would be class a { public function a() {}

 

Anyway..

 

You forgot to declare the functions static, since you're accessing them in a static way.

 

This works:

 

<?php
class a
{
    protected static function test()
    {
        print_r(self::$_data_map);
    }
    
    protected static $_data_map;
}

class b extends a
{
    public function __construct()
    {
        parent::$_data_map = array("a" => "b");
    }
    
    public static function test()
    {
        parent::test();
    }
}

$a = new a();
$b = new b();

$b->test();




?>

[Liquid Fire]

no, i don't want it to be static.  I want every class that extends from this class to have its own one(not every class is going ot have the same data map).  If it has to be static then i will have to declare in it each class.

[KevinM1]

I don't believe parent classes (in your example, class a) can have knowledge of their child classes (class b).  Child classes, however, can have knowledge (properties and methods) of their parent class.  So, if you have a super class that is the basis of all your datamap stuff, the child classes will have the same types of properties and methods as those that are either public or protected in the parent class.

 

So:

<?php

class DataMapper{
   protected $dataMap;

   protected function test(){
      print_r($this->dataMap);
   }
}

class UniqueMapper extends DataMapper{
   public function __construct(){
      $this->dataMap = array("a" => "b");
   }
}

class ComplexMapper extends DataMapper{
   public function __construct($key, $value){
      $this->dataMap = array($key => $value);
   }
}

$unique = new UniqueMapper();
$complex = new ComplexMapper("name", "Bubba");

$unique->test(); //prints a => b
$complex->test(); //prints name => Bubba

?>

 

In this example, even though all classes have a $dataMap property, it's not the same exact one.  Extending a class/using inheritence doesn't copy data.  It just tells the child class that part of its mold came from the parent class.

[keeB]

I'm pretty sure Nightslyr is correct in his estimation. At least, that's my experience.

[Daniel0]

keeB: You don't need methods to be static in order to use parent::