Observer

Author: maxsite

Observer/index.php

@@ -0,0 +1,123 @@
+<?php
+
+/**
+ * Design pattern "Observer" (Behavioral)
+ * This is demo code
+ * See for details: http://maxsite.org/page/php-patterns
+ */
+
+/**
+ * Observable use standart interface SplSubject
+ */
+class Observable implements \SplSubject
+{
+ /** 
+ * list of observers
+ */
+ private $observers;
+
+ /**
+ * create standart class SplObjectStorage
+ */
+ function __construct()
+ {
+ $this->observers = new SplObjectStorage();
+ }
+
+ /**
+ * standart method of SplObjectStorage
+ */
+ function attach(SplObserver $observer)
+ {
+ $this->observers->attach($observer);
+ }
+
+ /**
+ * standart method of SplObjectStorage
+ */
+ function detach(SplObserver $observer)
+ {
+ $this->observers->detach($observer);
+ }
+
+ /**
+ * send notify
+ */
+ function notify()
+ {
+ foreach ($this->observers as $obj) {
+ $obj->update($this);
+ }
+ }
+}
+
+/**
+ * Observer use standart interface SplObserver
+ */
+class Observer1 implements \SplObserver
+{
+ /**
+ * get notify from Observable
+ */
+ function update(SplSubject $subject)
+ {
+ echo 'update Observer1<br>';
+ }
+}
+
+/**
+ * another class for Observer
+ */
+class Observer2 implements \SplObserver
+{
+ function update(SplSubject $subject)
+ {
+ echo 'update Observer2<br>';
+ }
+}
+
+/**
+ * demo
+ */
+
+/**
+ * create Observable
+ */
+$observable = new Observable();
+
+/**
+ * create Observers
+ */
+$o1 = new Observer1();
+$o2 = new Observer2();
+
+/**
+ * attach Observers to Observable
+ */
+$observable->attach($o1);
+$observable->attach($o2);
+
+/**
+ * send notify
+ */
+$observable->notify();
+/*
+ update Observer1
+ update Observer2
+ */
+
+/**
+ * exclude Observer1
+ */
+$observable->detach($o1);
+
+/**
+ * send notify
+ */
+$observable->notify();
+/*
+ update Observer2
+ */
+
+
+# end of file

README.md

@@ -13,6 +13,7 @@ See details on http://maxsite.org/page/php-patterns
 * "Builder" (Creational)
 * "Strategy" (Behavioral)
 * "Adapter" (Structural)
+* "Observer" (Behavioral)
 
 
 (c) MaxSite.org, 2019, http://maxsite.org/