PHP observer pattern / magic setter / proxing

I'm looking for a way to monitor when a variable in my class gets set.

For example if I have the following class:

class MyClass  {
    public $myVariable;
} 

And somewhere in my code I do:

$class = new MyClass();
$class->myVariable = "value";

I would like to be able to "hook" into the setter of myVaria开发者_Go百科ble. So when I call $class->myVariable = "Value"; a filter would start that checks if the new value equals "Value" and if so, throws an Exception.

define your attribute as private or protected, as usual.

Then use the magic method __set() to catch the access.

Best regards

Raffael