From d2e86f1c35074457dc49bad6a7ddca3bc5a9e379 Mon Sep 17 00:00:00 2001
From: Trismegiste <florent.g@allopneus.com>
Date: Sun, 12 May 2013 14:25:17 +0200
Subject: [PATCH 1/2] mediator in one pass

---
 Mediator/Colleague.php          | 31 +++++++++++++++++++
 Mediator/Mediator.php           | 53 +++++++++++++++++++++++++++++++++
 Mediator/MediatorInterface.php  | 21 +++++++++++++
 Mediator/Subsystem/Client.php   | 27 +++++++++++++++++
 Mediator/Subsystem/Database.php | 22 ++++++++++++++
 Mediator/Subsystem/Server.php   | 23 ++++++++++++++
 Tests/Mediator/MediatorTest.php | 36 ++++++++++++++++++++++
 7 files changed, 213 insertions(+)
 create mode 100644 Mediator/Colleague.php
 create mode 100644 Mediator/Mediator.php
 create mode 100644 Mediator/MediatorInterface.php
 create mode 100644 Mediator/Subsystem/Client.php
 create mode 100644 Mediator/Subsystem/Database.php
 create mode 100644 Mediator/Subsystem/Server.php
 create mode 100644 Tests/Mediator/MediatorTest.php

diff --git a/Mediator/Colleague.php b/Mediator/Colleague.php
new file mode 100644
index 0000000..e410e86
--- /dev/null
+++ b/Mediator/Colleague.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Mediator;
+
+/**
+ * Colleague is an abstract colleague who works together but he only knows
+ * the Mediator, not other colleague.
+ */
+abstract class Colleague
+{
+
+    // this ensures no change in subclasses
+    private $mediator;
+
+    // for subclasses
+    protected function getMediator()
+    {
+        return $this->mediator;
+    }
+
+    public function __construct(MediatorInterface $medium)
+    {
+        // in this way, we are sure the concrete colleague knows the mediator
+        $this->mediator = $medium;
+    }
+
+}
\ No newline at end of file
diff --git a/Mediator/Mediator.php b/Mediator/Mediator.php
new file mode 100644
index 0000000..d6edb8c
--- /dev/null
+++ b/Mediator/Mediator.php
@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Mediator;
+
+use DesignPatterns\Mediator\Subsystem;
+
+/**
+ * Mediator is the concrete Mediator for this design pattern.
+ * 
+ * This pattern provides an easy to decouple many components working together.
+ * It is a good alternative over Observer IF you have a "central intelligence",
+ * like a controller (but not in the sense of the MVC).
+ * 
+ * All objects (called Colleague) are coupled only to the MediatorInterface and
+ * it is a good thing because in OOP, one good friend is better than many unreliable.
+ * 
+ * In this example, I have made a "Hello World" with the Mediator Pattern, have fun (^_^)
+ */
+class Mediator implements MediatorInterface
+{
+
+    // you could have an array
+    protected $server;
+    protected $database;
+    protected $client;
+
+    public function setColleague(Subsystem\Database $db, Subsystem\Client $cl, Subsystem\Server $srv)
+    {
+        $this->database = $db;
+        $this->server = $srv;
+        $this->client = $cl;
+    }
+
+    public function makeRequest()
+    {
+        $this->server->process();
+    }
+
+    public function queryDb()
+    {
+        return $this->database->getData();
+    }
+
+    public function sendResponse($content)
+    {
+        $this->client->output($content);
+    }
+
+}
\ No newline at end of file
diff --git a/Mediator/MediatorInterface.php b/Mediator/MediatorInterface.php
new file mode 100644
index 0000000..019ad4e
--- /dev/null
+++ b/Mediator/MediatorInterface.php
@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Mediator;
+
+/**
+ * MediatorInterface is a contract for the Mediator
+ * This interface is not mandatory but it is better for LSP concerns
+ */
+interface MediatorInterface
+{
+
+    function sendResponse($content);
+
+    function makeRequest();
+
+    function queryDb();
+}
\ No newline at end of file
diff --git a/Mediator/Subsystem/Client.php b/Mediator/Subsystem/Client.php
new file mode 100644
index 0000000..c4b082a
--- /dev/null
+++ b/Mediator/Subsystem/Client.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Mediator\Subsystem;
+
+use DesignPatterns\Mediator\Colleague;
+
+/**
+ * Client is a client that make request et get response
+ */
+class Client extends Colleague
+{
+
+    public function request()
+    {
+        $this->getMediator()->makeRequest();
+    }
+
+    public function output($content)
+    {
+        echo $content;
+    }
+
+}
\ No newline at end of file
diff --git a/Mediator/Subsystem/Database.php b/Mediator/Subsystem/Database.php
new file mode 100644
index 0000000..dd7bb01
--- /dev/null
+++ b/Mediator/Subsystem/Database.php
@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Mediator\Subsystem;
+
+use DesignPatterns\Mediator\Colleague;
+
+/**
+ * Database is a database service
+ */
+class Database extends Colleague
+{
+
+    public function getData()
+    {
+        return "World";
+    }
+
+}
\ No newline at end of file
diff --git a/Mediator/Subsystem/Server.php b/Mediator/Subsystem/Server.php
new file mode 100644
index 0000000..2f30c57
--- /dev/null
+++ b/Mediator/Subsystem/Server.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Mediator\Subsystem;
+
+use DesignPatterns\Mediator\Colleague;
+
+/**
+ * Server serves responses
+ */
+class Server extends Colleague
+{
+
+    public function process()
+    {
+        $data = $this->getMediator()->queryDb();
+        $this->getMediator()->sendResponse("Hello $data");
+    }
+
+}
\ No newline at end of file
diff --git a/Tests/Mediator/MediatorTest.php b/Tests/Mediator/MediatorTest.php
new file mode 100644
index 0000000..b673985
--- /dev/null
+++ b/Tests/Mediator/MediatorTest.php
@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Tests\Mediator;
+
+use DesignPatterns\Mediator\Mediator;
+use DesignPatterns\Mediator\Subsystem\Database;
+use DesignPatterns\Mediator\Subsystem\Client;
+use DesignPatterns\Mediator\Subsystem\Server;
+
+/**
+ * MediatorTest tests hello world
+ */
+class MediatorTest extends \PHPUnit_Framework_TestCase
+{
+
+    protected $client;
+
+    protected function setUp()
+    {
+        $media = new Mediator();
+        $this->client = new Client($media);
+        $media->setColleague(new Database($media), $this->client, new Server($media));
+    }
+
+    public function testOutputHelloWorld()
+    {
+        // testing if Hello World is output :
+        $this->expectOutputString('Hello World');
+        $this->client->request();
+    }
+
+}
\ No newline at end of file

From a3648c449e29eaa98f1dac5dfc27e7f56b5d3a86 Mon Sep 17 00:00:00 2001
From: Trismegiste <florent.g@allopneus.com>
Date: Sun, 12 May 2013 14:32:16 +0200
Subject: [PATCH 2/2] adding comments

---
 Mediator/Mediator.php           | 5 +++--
 README.markdown                 | 2 +-
 Tests/Mediator/MediatorTest.php | 3 +++
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/Mediator/Mediator.php b/Mediator/Mediator.php
index d6edb8c..98b34a1 100644
--- a/Mediator/Mediator.php
+++ b/Mediator/Mediator.php
@@ -15,8 +15,9 @@ use DesignPatterns\Mediator\Subsystem;
  * It is a good alternative over Observer IF you have a "central intelligence",
  * like a controller (but not in the sense of the MVC).
  * 
- * All objects (called Colleague) are coupled only to the MediatorInterface and
- * it is a good thing because in OOP, one good friend is better than many unreliable.
+ * All components (called Colleague) are only coupled to the MediatorInterface and
+ * it is a good thing because in OOP, one good friend is better than many. This
+ * is the key-feature of this pattern.
  * 
  * In this example, I have made a "Hello World" with the Mediator Pattern, have fun (^_^)
  */
diff --git a/README.markdown b/README.markdown
index 3742786..168fc4a 100644
--- a/README.markdown
+++ b/README.markdown
@@ -23,4 +23,4 @@ Changes I've made :
 * Fixing the Adapter Pattern because it was buggy and incomplete (+ Tests)
 * Adding Template Method Pattern (+ Tests)
 * Adding Builder Pattern (+ Tests)
-* 
\ No newline at end of file
+* Adding Mediator Pattern (+ Tests)
\ No newline at end of file
diff --git a/Tests/Mediator/MediatorTest.php b/Tests/Mediator/MediatorTest.php
index b673985..f4f689d 100644
--- a/Tests/Mediator/MediatorTest.php
+++ b/Tests/Mediator/MediatorTest.php
@@ -30,7 +30,10 @@ class MediatorTest extends \PHPUnit_Framework_TestCase
     {
         // testing if Hello World is output :
         $this->expectOutputString('Hello World');
+        // as you see, the 3 components Client, Server and Database are totally decoupled
         $this->client->request();
+        // Anyway, it remains complexity in the Mediator that's why the pattern
+        // Observer is preferable in mnay situations.
     }
 
 }
\ No newline at end of file