<?php
class NoticeBoard{
private $_observers = array();
public function addNote( $name ) {
foreach( $this->_observers as $obs )
$obs->onChanged( $this, $name );
}
public function addObserver( $observer ) {
$this->_observers []= $observer;
}
}
class Student{
public function onChanged( $sender, $args ) {
echo("The ".__CLASS__." is informed '$args' \n" );
}
}
class Teacher{
public function onChanged( $sender, $args ) {
echo( "The ".__CLASS__." is informed '$args' \n" );
}
}
$s = new Student();
$t = new Teacher();
$nb = new NoticeBoard();
$nb -> addObserver($s);
$nb -> addObserver($t);
$nb->addNote('Due storm exams are postponed.');
?>
Result is
The Student is informed 'Due storm exams are postponed.'
The Teacher is informed 'Due storm exams are postponed.'
