Merge branch 'decorator-the-right-way'

Decorator/Decorator.php

@@ -1,6 +1,6 @@
 <?php
 
-namespace DesignPatterns;
+namespace DesignPatterns\Decorator;
 
 /**
  * Decorator pattern
@@ -15,60 +15,25 @@ namespace DesignPatterns;
  *
  */
  
-interface Renderer
-{
-    public function renderData();
-}
 
-class Webservice implements Renderer
-{
-    protected $_data;
-
-    public function __construct($data)
-    {
-        $this->_data = $data;
-    }
-
-    public function renderData()
-    {
-        return $this->_data;
-    }
-}
-
-abstract class Decorator
+/** 
+ * the Deoorator MUST implement the Renderer contract, this is the key-feature
+ * of this design pattern. If not, this is no longer a Decorator but just a dumb
+ * wrapper.
+ */
+abstract class Decorator implements Renderer
 {
     protected $_wrapped;
     
-    public function __construct($wrappable)
+    /**
+     * You must type-hint the wrapped component :
+     * It ensures you can call renderData() in the subclasses !
+     * 
+     * @param Renderer $wrappable
+     */
+    public function __construct(Renderer $wrappable)
     {
         $this->_wrapped = $wrappable;
     }
 }
 
-class RenderInJson extends Decorator implements Renderer
-{
-    public function renderData()
-    {
-        $output = $this->_wrapped->renderData();
-        return json_encode($output);
-    }
-}
-
-class RenderInXml extends Decorator implements Renderer
-{
-    public function renderData()
-    {
-        $output = $this->_wrapped->renderData();
-        // do some fany conversion to xml from array ...
-        return simplexml_load_string($output);
-    }
-}
-
-// Create a normal service
-$service = new Webservice(array('foo' => 'bar'));
-
-// Wrap service with a JSON decorator for renderers
-$service = new RenderInJson($service);
-// Our Renderer will now output JSON instead of an array
-
-echo $service->renderData();

Decorator/RenderInJson.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace DesignPatterns\Decorator;
+
+class RenderInJson extends Decorator
+{
+    public function renderData()
+    {
+        $output = $this->_wrapped->renderData();
+        return json_encode($output);
+    }
+}

Decorator/RenderInXml.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace DesignPatterns\Decorator;
+
+class RenderInXml extends Decorator
+{
+    public function renderData()
+    {
+        $output = $this->_wrapped->renderData();
+        // do some fany conversion to xml from array ...
+        $doc = new \DOMDocument();
+        foreach ($output as $key => $val) {
+            $doc->appendChild($doc->createElement('foo', 'bar'));
+        }
+        
+        return $doc->saveXML();
+    }
+}

Decorator/Renderer.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace DesignPatterns\Decorator;
+ 
+interface Renderer
+{
+    public function renderData();
+}

Decorator/Webservice.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace DesignPatterns\Decorator;
+
+class Webservice implements Renderer
+{
+    protected $_data;
+
+    public function __construct($data)
+    {
+        $this->_data = $data;
+    }
+
+    public function renderData()
+    {
+        return $this->_data;
+    }
+}

Tests/Decorator/DecoratorTest.php

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * DesignPatternPHP
+ */
+
+namespace DesignPatterns\Tests\Decorator;
+
+use DesignPatterns\Decorator;
+
+/**
+ * DecoratorTest tests the decorator pattern
+ */
+class DecoratorTest extends \PHPUnit_Framework_TestCase
+{
+
+    protected $service;
+
+    protected function setUp()
+    {
+        $this->service = new Decorator\Webservice(array('foo' => 'bar'));
+    }
+
+    public function testJsonDecorator()
+    {
+        // Wrap service with a JSON decorator for renderers
+        $service = new Decorator\RenderInJson($this->service);
+        // Our Renderer will now output JSON instead of an array
+        $this->assertEquals('{"foo":"bar"}', $service->renderData());
+    }
+
+    public function testXmlDecorator()
+    {
+        // Wrap service with a JSON decorator for renderers
+        $service = new Decorator\RenderInXml($this->service);
+        // Our Renderer will now output XML instead of an array
+        $this->assertXmlStringEqualsXmlString('<?xml version="1.0"?><foo>bar</foo>', $service->renderData());
+    }
+
+}