Merge branch 'facade-a-more-abstract-example'

Facade/Computer.php

@@ -0,0 +1,58 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Facade;
+
+/**
+ * The primary goal of a Facade Pattern is not to avoid you to read the manual of
+ * a complex API. It's only a side-effect.
+ * 
+ * The first goal is to reduce coupling and folow the Law of Demeter.
+ * 
+ * A Facade is meant to decouple a client and a sub-system by embedding
+ * many (but sometimes just one) interface, and of course to reduce complexity.
+ * 
+ * 1. A facade does not forbid you the access to the sub-system
+ * 2. You can (you should) have multiple facades for one sub-system
+ * 
+ * That's why a good facade has no "new" in it. If there are multiple creations
+ * for each method, it is not a Facade, it's a Builder or a 
+ * [Abstract|Static|Simple] Factory [Method]. 
+ *
+ * The best facade has no new and a constructor with interface-type-hinted parameters.
+ * If you need creation of new instances, use Factory as argument. 
+ * 
+ */
+class Computer
+{
+
+    protected $opsys;
+    protected $bios;
+
+    /**
+     * This is the perfect time to use a dependency injection container
+     * to creaate an instance of this class
+     */
+    public function __construct(BiosInterface $bios, OsInterface $os)
+    {
+        $this->bios = $bios;
+        $this->opsys = $os;
+    }
+
+    public function turnOn()
+    {
+        $this->bios->execute();
+        $this->bios->waitForKeyPress();
+        $this->bios->launch($this->opsys);
+    }
+
+    public function turnOff()
+    {
+        $this->opsys->halt();
+        $this->bios->powerDown();
+    }
+
+}

Tests/Facade/FacadeTest.php

@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Tests\Facade;
+
+use DesignPatterns\Facade\Computer;
+use DesignPatterns\Facade\Installer;
+
+/**
+ * FacadeTest shows example of facades
+ */
+class FacadeTest extends \PHPUnit_Framework_TestCase
+{
+
+    public function getComputer()
+    {
+        $bios = $this->getMockBuilder('DesignPatterns\Facade\BiosInterface')
+                ->setMethods(array('launch', 'execute', 'waitForKeyPress'))
+                ->disableAutoload()
+                ->getMock();
+        $operatingSys = $this->getMockBuilder('DesignPatterns\Facade\OsInterface')
+                ->setMethods(array('getName'))
+                ->disableAutoload()
+                ->getMock();
+        $bios->expects($this->once())
+                ->method('launch')
+                ->with($operatingSys);
+        $operatingSys
+                ->expects($this->once())
+                ->method('getName')
+                ->will($this->returnValue('Linux'));
+
+        $facade = new Computer($bios, $operatingSys);
+        return array(array($facade, $operatingSys));
+    }
+
+    /**
+     * @dataProvider getComputer
+     */
+    public function testComputerOn(Computer $facade, $os)
+    {
+        // interface is simpler :
+        $facade->turnOn();
+        // but I can access to lower component
+        $this->assertEquals('Linux', $os->getName());
+    }
+
+}