improved Flyweight

Author: Dominik Liebler

Structural/Flyweight/CharacterFlyweight.php renamed to Structural/Flyweight/Character.php

@@ -7,7 +7,7 @@
  * Implements the flyweight interface and adds storage for intrinsic state, if any.
  * Instances of concrete flyweights are shared by means of a factory.
  */
-class CharacterFlyweight implements FlyweightInterface
+class Character implements Text
 {
     /**
      * Any state stored by the concrete flyweight must be independent of its context.

Structural/Flyweight/FlyweightFactory.php

@@ -20,21 +20,27 @@ Code
 
 You can also find this code on `GitHub`_
 
-FlyweightInterface.php
+Text.php
 
-.. literalinclude:: FlyweightInterface.php
+.. literalinclude:: Text.php
    :language: php
    :linenos:
 
-CharacterFlyweight.php
+Word.php
 
-.. literalinclude:: CharacterFlyweight.php
+.. literalinclude:: Word.php
    :language: php
    :linenos:
 
-FlyweightFactory.php
+Character.php
 
-.. literalinclude:: FlyweightFactory.php
+.. literalinclude:: Character.php
+   :language: php
+   :linenos:
+
+TextFactory.php
+
+.. literalinclude:: TextFactory.php
    :language: php
    :linenos:
 

Structural/Flyweight/README.rst

@@ -3,7 +3,7 @@
 
 namespace DesignPatterns\Structural\Flyweight\Tests;
 
-use DesignPatterns\Structural\Flyweight\FlyweightFactory;
+use DesignPatterns\Structural\Flyweight\TextFactory;
 use PHPUnit\Framework\TestCase;
 
 class FlyweightTest extends TestCase
@@ -14,20 +14,29 @@ class FlyweightTest extends TestCase
 
     public function testFlyweight()
     {
-        $factory = new FlyweightFactory();
+        $factory = new TextFactory();
 
-        foreach ($this->characters as $char) {
-            foreach ($this->fonts as $font) {
-                $flyweight = $factory->get($char);
-                $rendered = $flyweight->render($font);
+        for ($i = 0; $i <= 10; $i++) {
+            foreach ($this->characters as $char) {
+                foreach ($this->fonts as $font) {
+                    $flyweight = $factory->get($char);
+                    $rendered = $flyweight->render($font);
 
-                $this->assertSame(sprintf('Character %s with font %s', $char, $font), $rendered);
+                    $this->assertSame(sprintf('Character %s with font %s', $char, $font), $rendered);
+                }
             }
         }
 
+        foreach ($this->fonts as $word) {
+            $flyweight = $factory->get($word);
+            $rendered = $flyweight->render('foobar');
+
+            $this->assertSame(sprintf('Word %s with font foobar', $word), $rendered);
+        }
+
         // Flyweight pattern ensures that instances are shared
         // instead of having hundreds of thousands of individual objects
         // there must be one instance for every char that has been reused for displaying in different fonts
-        $this->assertCount(count($this->characters), $factory);
+        $this->assertCount(count($this->characters) + count($this->fonts), $factory);
     }
 }

Structural/Flyweight/Tests/FlyweightTest.php

@@ -3,7 +3,10 @@
 
 namespace DesignPatterns\Structural\Flyweight;
 
-interface FlyweightInterface
+/**
+ * This is the interface that all flyweights need to implement
+ */
+interface Text
 {
     public function render(string $extrinsicState): string;
 }

Structural/Flyweight/FlyweightInterface.php renamed to Structural/Flyweight/Text.php

@@ -0,0 +1,39 @@
+<?php
+declare(strict_types=1);
+
+namespace DesignPatterns\Structural\Flyweight;
+
+/**
+ * A factory manages shared flyweights. Clients should not instantiate them directly,
+ * but let the factory take care of returning existing objects or creating new ones.
+ */
+class TextFactory implements \Countable
+{
+    /**
+     * @var Text[]
+     */
+    private $charPool = [];
+
+    public function get(string $name): Text
+    {
+        if (!isset($this->charPool[$name])) {
+            $this->charPool[$name] = $this->create($name);
+        }
+
+        return $this->charPool[$name];
+    }
+
+    private function create(string $name): Text
+    {
+        if (strlen($name) == 1) {
+            return new Character($name);
+        } else {
+            return new Word($name);
+        }
+    }
+
+    public function count(): int
+    {
+        return count($this->charPool);
+    }
+}

Structural/Flyweight/TextFactory.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace DesignPatterns\Structural\Flyweight;
+
+class Word implements Text
+{
+    /**
+     * @var string
+     */
+    private $name;
+
+    public function __construct(string $name)
+    {
+        $this->name = $name;
+    }
+
+    public function render(string $font): string
+    {
+        return sprintf('Word %s with font %s', $this->name, $font);
+    }
+}