Observer example

Author: hbrawnak

Observer/index.php

@@ -0,0 +1,79 @@
+<?php
+
+interface Subject
+{
+    public function attach($observable);
+
+    public function detach($observer);
+
+    public function notify();
+}
+
+interface Observer
+{
+    public function handle();
+}
+
+class Login implements Subject
+{
+    protected $observers = [];
+
+    public function attach($observable)
+    {
+        if (is_array($observable)) {
+            foreach ($observable as $observer) {
+                if (!$observer instanceof Observer)
+                    throw new Exception();
+                $this->attach($observer);
+            }
+
+            return;
+        }
+
+        $this->observers[] = $observable;
+
+        return;
+    }
+
+    public function detach($index)
+    {
+        unset($this->observers[$index]);
+    }
+
+    public function notify()
+    {
+        foreach ($this->observers as $observer) {
+            $observer->handle();
+        }
+    }
+
+    public function fire()
+    {
+        $this->notify();
+    }
+}
+
+class LogHandler implements Observer
+{
+    public function handle()
+    {
+        echo "Logged in something \n";
+    }
+}
+
+class EmailHandler implements Observer
+{
+    public function handle()
+    {
+        echo "Fire of an email \n";
+    }
+}
+
+$login = new Login();
+$login->attach([
+    new LogHandler(),
+    new EmailHandler()
+]);
+
+$login->fire();
+