PHP7 Observer

Behavioral/Observer/Tests/ObserverTest.php

@@ -5,65 +5,16 @@ namespace DesignPatterns\Behavioral\Observer\Tests;
 use DesignPatterns\Behavioral\Observer\User;
 use DesignPatterns\Behavioral\Observer\UserObserver;
 
-/**
- * ObserverTest tests the Observer pattern.
- */
 class ObserverTest extends \PHPUnit_Framework_TestCase
 {
-    protected $observer;
-
-    protected function setUp()
+    public function testChangeInUserLeadsToUserObserverBeingNotified()
     {
-        $this->observer = new UserObserver();
-    }
+        $observer = new UserObserver();
 
-    /**
-     * Tests the notification.
-     */
-    public function testNotify()
-    {
-        $this->expectOutputString('DesignPatterns\Behavioral\Observer\User has been updated');
-        $subject = new User();
+        $user = new User();
+        $user->attach($observer);
 
-        $subject->attach($this->observer);
-        $subject->property = 123;
-    }
-
-    /**
-     * Tests the subscribing.
-     */
-    public function testAttachDetach()
-    {
-        $subject = new User();
-        $reflection = new \ReflectionProperty($subject, 'observers');
-
-        $reflection->setAccessible(true);
-        /** @var \SplObjectStorage $observers */
-        $observers = $reflection->getValue($subject);
-
-        $this->assertInstanceOf('SplObjectStorage', $observers);
-        $this->assertFalse($observers->contains($this->observer));
-
-        $subject->attach($this->observer);
-        $this->assertTrue($observers->contains($this->observer));
-
-        $subject->detach($this->observer);
-        $this->assertFalse($observers->contains($this->observer));
-    }
-
-    /**
-     * Tests the update() invocation on a mockup.
-     */
-    public function testUpdateCalling()
-    {
-        $subject = new User();
-        $observer = $this->createMock('SplObserver');
-        $subject->attach($observer);
-
-        $observer->expects($this->once())
-            ->method('update')
-            ->with($subject);
-
-        $subject->notify();
+        $user->changeEmail('foo@bar.com');
+        $this->assertCount(1, $observer->getChangedUsers());
     }
 }

Behavioral/Observer/User.php

@@ -3,60 +3,42 @@
 namespace DesignPatterns\Behavioral\Observer;
 
 /**
- * Observer pattern : The observed object (the subject).
- *
- * The subject maintains a list of Observers and sends notifications.
+ * User implements the observed object (called Subject), it maintains a list of observers and sends notifications to
+ * them in case changes are made on the User object
  */
 class User implements \SplSubject
 {
     /**
-     * user data.
-     *
-     * @var array
+     * @var string
      */
-    protected $data = array();
+    private $email;
 
     /**
-     * observers.
-     *
      * @var \SplObjectStorage
      */
-    protected $observers;
+    private $observers;
 
     public function __construct()
     {
         $this->observers = new \SplObjectStorage();
     }
 
-    /**
-     * attach a new observer.
-     *
-     * @param \SplObserver $observer
-     *
-     * @return void
-     */
     public function attach(\SplObserver $observer)
     {
         $this->observers->attach($observer);
     }
 
-    /**
-     * detach an observer.
-     *
-     * @param \SplObserver $observer
-     *
-     * @return void
-     */
     public function detach(\SplObserver $observer)
     {
         $this->observers->detach($observer);
     }
 
-    /**
-     * notify observers.
-     *
-     * @return void
-     */
+    public function changeEmail(string $email)
+    {
+        $this->email = $email;
+        $this->notify();
+    }
+
     public function notify()
     {
         /** @var \SplObserver $observer */
@@ -64,21 +46,4 @@ class User implements \SplSubject
             $observer->update($this);
         }
     }
-
-    /**
-     * Ideally one would better write setter/getter for all valid attributes and only call notify()
-     * on attributes that matter when changed.
-     *
-     * @param string $name
-     * @param mixed  $value
-     *
-     * @return void
-     */
-    public function __set($name, $value)
-    {
-        $this->data[$name] = $value;
-
-        // notify the observers, that user has been updated
-        $this->notify();
-    }
 }

Behavioral/Observer/UserObserver.php

@@ -2,19 +2,28 @@
 
 namespace DesignPatterns\Behavioral\Observer;
 
-/**
- * class UserObserver.
- */
 class UserObserver implements \SplObserver
 {
     /**
-     * This is the only method to implement as an observer.
-     * It is called by the Subject (usually by SplSubject::notify() ).
+     * @var User[]
+     */
+    private $changedUsers = [];
+
+    /**
+     * It is called by the Subject, usually by SplSubject::notify()
      *
      * @param \SplSubject $subject
      */
     public function update(\SplSubject $subject)
     {
-        echo get_class($subject).' has been updated';
+        $this->changedUsers[] = clone $subject;
+    }
+
+    /**
+     * @return User[]
+     */
+    public function getChangedUsers(): array
+    {
+        return $this->changedUsers;
     }
 }

Behavioral/Observer/uml/Observer.uml

@@ -1,27 +1,26 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<Diagram>
-  <ID>PHP</ID>
-  <OriginalElement>\DesignPatterns\Behavioral\Observer\User</OriginalElement>
-  <nodes>
-    <node x="239.0" y="0.0">\DesignPatterns\Behavioral\Observer\UserObserver</node>
-    <node x="0.0" y="137.0">\DesignPatterns\Behavioral\Observer\User</node>
-    <node x="8.0" y="0.0">\SplSubject</node>
-  </nodes>
-  <notes />
-  <edges>
-    <edge source="\DesignPatterns\Behavioral\Observer\User" target="\SplSubject">
-      <point x="0.0" y="-74.0" />
-      <point x="0.0" y="43.5" />
-    </edge>
-  </edges>
-  <settings layout="Hierarchic Group" zoom="1.0" x="186.0" y="142.5" />
-  <SelectedNodes />
-  <Categories>
-    <Category>Fields</Category>
-    <Category>Constants</Category>
-    <Category>Constructors</Category>
-    <Category>Methods</Category>
-  </Categories>
-  <VISIBILITY>private</VISIBILITY>
-</Diagram>
-
+<?xml version="1.0" encoding="UTF-8"?>
+<Diagram>
+  <ID>PHP</ID>
+  <OriginalElement>\DesignPatterns\Behavioral\Observer\UserObserver</OriginalElement>
+  <nodes>
+    <node x="215.0" y="112.0">\DesignPatterns\Behavioral\Observer\UserObserver</node>
+    <node x="229.5" y="7.0">\SplObserver</node>
+    <node x="-29.0" y="25.0">\DesignPatterns\Behavioral\Observer\User</node>
+  </nodes>
+  <notes />
+  <edges>
+    <edge source="\DesignPatterns\Behavioral\Observer\UserObserver" target="\SplObserver">
+      <point x="0.0" y="-48.0" />
+      <point x="0.0" y="25.5" />
+    </edge>
+  </edges>
+  <settings layout="Hierarchic Group" zoom="1.0" x="58.0" y="91.0" />
+  <SelectedNodes />
+  <Categories>
+    <Category>Fields</Category>
+    <Category>Constants</Category>
+    <Category>Methods</Category>
+  </Categories>
+  <VISIBILITY>private</VISIBILITY>
+</Diagram>
+