March 30, 2012
How to create a "listening(waiting?)" method
Question by Andrius Naruševičius
Lets say I have:
class X
{
function a()
{
echo "Hello, ";
}
function b()
{
echo "John!";
}
}
and then
Y = new X();
Y->a();
but once the method a is called, I also want the method b called immediately after it (so it kind of listens(waits?) till the moment when a is called and finished), so the output is
Hello, John
Is it possible to do that, and how that should look?
And no, calling $this->b(); at the end of method a is NOT a solution to what I want to do 
Thanks in advance
Answer by Starx
You are searching for observer pattern. Read some example from the internet, you should be able to do what you are attempting.
However, A very simple example of using observer pattern:
class X
{
private $observer;
public function __construct() {
$this -> observer = new XObserver();
}
function a() {
echo "Hello,";
$this -> observer -> aExecuted($this);
}
function b() {
echo "John!";
}
}
class XObserver {
public function aExecuted($obj) {
return $obj -> b();
}
}
