Can you explain how Zend's Action controller operating?

_{Sorry for constantly re-editing my question but looks like this is the only way to ask it properly.}

My original problem is the following pseudo-code (a controller and it's parent) isn't working as i would like to:

class Parent {
    var $data = array();
    public function __construct( OtherClass $otherClass ) {
        $this->data = $otherClass->getData(); //contains some => thing
        $this->init($otherClass->getClassName());
    }
    public function init( $className ) {
        new $className; //new Child
    }
    public function __get( $name ) {
        return array_key_exists($name, $this->data) ? $this->data[$name] : null;
    }
}

class Child extends Parent {
    public function __construct() {
        echo $this->some; //won't return 'thing';
    }
}

fireeyedboy helped me a lot (thank you) and pointed out Zend_Controller_Action is doing what i want but i can't understand how they do it?

Original question

I know th开发者_如何学JAVAere was some similar questions here but i cannot dump them. Also i know i can reverse the whole process so i can initialize Child first then call parent::__construct but this seems unwanted for me. How can i access Parent variables easily in my case?

Update:

Let me clarify a little bit. Child is an arbitrary controller. Parent is the mother of all controllers. Many frameworks are doing the same but controllers can utilize their parent controllers variables, methods or objects without calling parent::__construct (and therefore filling child class constructors with unnecessary arguments). I don't like to rewrite any of these frameworks but i'd like to understand how they're operating.

Your child class doesn't call parent constructor. Here's a fix:

class Child extends Parent {
   public function __construct() {
       parent::__construct();
       echo $this->some;
   }
}

Update: Parent classes' constructors aren't called automatically in PHP. See the documentation:

Note: Parent constructors are not called implicitly if the child class defines a constructor. In order to run a parent constructor, a call to parent::__construct() within the child constructor is required.

So what you're asking does not happen. Either you have misinterpreted the class structure or how they operate. Note that PHP also supports legacy constructor naming (at least until 5.3.3): If there is no __construct() method in a class, PHP assumes the constructor is named after the class (ie. class Foo { function Foo() {}) treats the Foo() method as constructor).

Injecting ANYTHING using controller's construct is generally a BAD PRACTICE! Problem lies in your design. What kind of object is OtherClass? Is it DB adapter? Is it ACL? Is it some helper class?

If you need external class in your controller I suggest using action helpers. That's what they are created for ;) Or create an action helper that will fetch this OtherClass from somewhere when needed.

You should NEVER use __construct() to do any of your dirty work. That's what init() is used for. But it has no params. And there is a reason for that - again - you should not inject dependencies like this ;)

Update: Note your class uses discouraged PHP4 member variable definition syntax. Try replacing your var with protected.

The problem is that your Child class does not call the base constructor.

Incidentally, Parent is not a valid class name in PHP. I have changed the class names for clarity. See below:

class ChildClass extends ParentClass {
   public function __construct() {
       parent::__construct(/* what goes here? */);
       echo $this->some;
   }
}

However, note the what goes here? part: your base class requires a reference to an OtherClass instance to be constructed. Therefore, since ChildClass IS-A ParentClass, it also needs to get such an instance somehow. You will need to either add a parameter to ChildClass::__construct and forward the value to parent::__construct, or somehow figure out a default value yourself.