introduced PostId and PostStatus and changed naming from Storage to Persistence

More/Repository/Domain/Post.php

@@ -5,10 +5,15 @@ namespace DesignPatterns\More\Repository\Domain;
 class Post
 {
     /**
-     * @var int
+     * @var PostId
      */
     private $id;
 
+    /**
+     * @var PostStatus
+     */
+    private $status;
+
     /**
      * @var string
      */
@@ -19,10 +24,11 @@ class Post
      */
     private $text;
 
-    public static function draft(int $id, string $title, string $text): Post
+    public static function draft(PostId $id, string $title, string $text): Post
     {
         return new self(
             $id,
+            PostStatus::fromString(PostStatus::STATE_DRAFT),
             $title,
             $text
         );
@@ -31,29 +37,37 @@ class Post
     public static function fromState(array $state): Post
     {
         return new self(
-            $state['id'],
+            PostId::fromInt($state['id']),
+            PostStatus::fromInt($state['statusId']),
             $state['title'],
             $state['text']
         );
     }
 
     /**
-     * @param int $id
-     * @param string $text
+     * @param PostId $id
+     * @param PostStatus $status
      * @param string $title
+     * @param string $text
      */
-    private function __construct(int $id, string $title, string $text)
+    private function __construct(PostId $id, PostStatus $status, string $title, string $text)
     {
         $this->id = $id;
+        $this->status = $status;
         $this->text = $text;
         $this->title = $title;
     }
 
-    public function getId(): int
+    public function getId(): PostId
     {
         return $this->id;
     }
 
+    public function getStatus(): PostStatus
+    {
+        return $this->status;
+    }
+
     public function getText(): string
     {
         return $this->text;

More/Repository/Domain/PostId.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace DesignPatterns\More\Repository\Domain;
+
+/**
+ * This is a perfect example of a value object that is identifiable by it's value alone and
+ * is guaranteed to be valid each time an instance is created. Another important property of value objects
+ * is immutability.
+ *
+ * Notice also the use of a named constructor (fromInt) which adds a little context when creating an instance.
+ */
+class PostId
+{
+    /**
+     * @var int
+     */
+    private $id;
+
+    public static function fromInt(int $id)
+    {
+        self::ensureIsValid($id);
+
+        return new self($id);
+    }
+
+    private function __construct(int $id)
+    {
+        $this->id = $id;
+    }
+
+    public function toInt(): int
+    {
+        return $this->id;
+    }
+
+    private static function ensureIsValid(int $id)
+    {
+        if ($id <= 0) {
+            throw new \InvalidArgumentException('Invalid PostId given');
+        }
+    }
+}

More/Repository/Domain/PostStatus.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace DesignPatterns\More\Repository\Domain;
+
+/**
+ * Like PostId, this is a value object which holds the value of the current status of a Post. It can be constructed
+ * either from a string or int and is able to validate itself. An instance can then be converted back to int or string.
+ */
+class PostStatus
+{
+    const STATE_DRAFT_ID = 1;
+    const STATE_PUBLISHED_ID = 2;
+
+    const STATE_DRAFT = 'draft';
+    const STATE_PUBLISHED = 'published';
+
+    private static $validStates = [
+        self::STATE_DRAFT_ID => self::STATE_DRAFT,
+        self::STATE_PUBLISHED_ID => self::STATE_PUBLISHED,
+    ];
+
+    /**
+     * @var int
+     */
+    private $id;
+
+    /**
+     * @var string
+     */
+    private $name;
+
+    public static function fromInt(int $statusId)
+    {
+        self::ensureIsValidId($statusId);
+
+        return new self($statusId, self::$validStates[$statusId]);
+    }
+
+    public static function fromString(string $status)
+    {
+        self::ensureIsValidName($status);
+
+        return new self(array_search($status, self::$validStates), $status);
+    }
+
+    private function __construct(int $id, string $name)
+    {
+        $this->id = $id;
+        $this->name = $name;
+    }
+
+    public function toInt(): int
+    {
+        return $this->id;
+    }
+
+    /**
+     * there is a reason that I avoid using __toString() as it operates outside of the stack in PHP
+     * and is therefor not able to operate well with exceptions
+     */
+    public function toString(): string
+    {
+        return $this->name;
+    }
+
+    private static function ensureIsValidId(int $status)
+    {
+        if (!in_array($status, array_keys(self::$validStates), true)) {
+            throw new \InvalidArgumentException('Invalid status id given');
+        }
+    }
+
+
+    private static function ensureIsValidName(string $status)
+    {
+        if (!in_array($status, self::$validStates, true)) {
+            throw new \InvalidArgumentException('Invalid status name given');
+        }
+    }
+}

More/Repository/InMemoryPersistence.php

@@ -2,7 +2,7 @@
 
 namespace DesignPatterns\More\Repository;
 
-class MemoryStorage implements Storage
+class InMemoryPersistence implements Persistence
 {
     /**
      * @var array

More/Repository/Persistence.php

@@ -2,7 +2,7 @@
 
 namespace DesignPatterns\More\Repository;
 
-interface Storage
+interface Persistence
 {
     public function generateId(): int;
 

More/Repository/PostRepository.php

@@ -3,9 +3,10 @@
 namespace DesignPatterns\More\Repository;
 
 use DesignPatterns\More\Repository\Domain\Post;
+use DesignPatterns\More\Repository\Domain\PostId;
 
 /**
- * This class is situated between Entity layer (class Post) and access object layer (MemoryStorage).
+ * This class is situated between Entity layer (class Post) and access object layer (Persistence).
  *
  * Repository encapsulates the set of objects persisted in a data store and the operations performed over them
  * providing a more object-oriented view of the persistence layer
@@ -16,26 +17,26 @@ use DesignPatterns\More\Repository\Domain\Post;
 class PostRepository
 {
     /**
-     * @var Storage
+     * @var Persistence
      */
     private $persistence;
 
-    public function __construct(Storage $persistence)
+    public function __construct(Persistence $persistence)
     {
         $this->persistence = $persistence;
     }
 
-    public function generateId(): int
+    public function generateId(): PostId
     {
-        return $this->persistence->generateId();
+        return PostId::fromInt($this->persistence->generateId());
     }
 
-    public function findById(int $id): Post
+    public function findById(PostId $id): Post
     {
         try {
-            $arrayData = $this->persistence->retrieve($id);
+            $arrayData = $this->persistence->retrieve($id->toInt());
         } catch (\OutOfBoundsException $e) {
-            throw new \OutOfBoundsException(sprintf('Post with id %d does not exist', $id), 0, $e);
+            throw new \OutOfBoundsException(sprintf('Post with id %d does not exist', $id->toInt()), 0, $e);
         }
 
         return Post::fromState($arrayData);
@@ -44,7 +45,8 @@ class PostRepository
     public function save(Post $post)
     {
         $this->persistence->persist([
-            'id' => $post->getId(),
+            'id' => $post->getId()->toInt(),
+            'statusId' => $post->getStatus()->toInt(),
             'text' => $post->getText(),
             'title' => $post->getTitle(),
         ]);

More/Repository/README.rst

@@ -33,7 +33,19 @@ You can also find this code on `GitHub`_
 
 Post.php
 
-.. literalinclude:: Post.php
+.. literalinclude:: Domain/Post.php
+   :language: php
+   :linenos:
+
+PostId.php
+
+.. literalinclude:: Domain/PostId.php
+   :language: php
+   :linenos:
+
+PostStatus.php
+
+.. literalinclude:: Domain/PostStatus.php
    :language: php
    :linenos:
 
@@ -43,18 +55,24 @@ PostRepository.php
    :language: php
    :linenos:
 
-MemoryStorage.php
+Persistence.php
 
-.. literalinclude:: MemoryStorage.php
+.. literalinclude:: InMemoryPersistence.php
+   :language: php
+   :linenos:
+
+InMemoryPersistence.php
+
+.. literalinclude:: InMemoryPersistence.php
    :language: php
    :linenos:
 
 Test
 ----
 
-Tests/RepositoryTest.php
+Tests/PostRepositoryTest.php
 
-.. literalinclude:: Tests/RepositoryTest.php
+.. literalinclude:: Tests/PostRepositoryTest.php
     :language: php
     :linenos:
 

More/Repository/Tests/PostRepositoryTest.php

@@ -2,7 +2,9 @@
 
 namespace DesignPatterns\More\Repository\Tests;
 
-use DesignPatterns\More\Repository\MemoryStorage;
+use DesignPatterns\More\Repository\Domain\PostId;
+use DesignPatterns\More\Repository\Domain\PostStatus;
+use DesignPatterns\More\Repository\InMemoryPersistence;
 use DesignPatterns\More\Repository\Domain\Post;
 use DesignPatterns\More\Repository\PostRepository;
 use PHPUnit\Framework\TestCase;
@@ -16,12 +18,12 @@ class PostRepositoryTest extends TestCase
 
     protected function setUp()
     {
-        $this->repository = new PostRepository(new MemoryStorage());
+        $this->repository = new PostRepository(new InMemoryPersistence());
     }
 
     public function testCanGenerateId()
     {
-        $this->assertEquals(1, $this->repository->generateId());
+        $this->assertEquals(1, $this->repository->generateId()->toInt());
     }
 
     /**
@@ -30,7 +32,7 @@ class PostRepositoryTest extends TestCase
      */
     public function testThrowsExceptionWhenTryingToFindPostWhichDoesNotExist()
     {
-        $this->repository->findById(42);
+        $this->repository->findById(PostId::fromInt(42));
     }
 
     public function testCanPersistPostDraft()
@@ -39,6 +41,9 @@ class PostRepositoryTest extends TestCase
         $post = Post::draft($postId, 'Repository Pattern', 'Design Patterns PHP');
         $this->repository->save($post);
 
+        $this->repository->findById($postId);
+
         $this->assertEquals($postId, $this->repository->findById($postId)->getId());
+        $this->assertEquals(PostStatus::STATE_DRAFT, $post->getStatus()->toString());
     }
 }

More/Repository/uml/Repository.uml

@@ -3,20 +3,24 @@
   <ID>PHP</ID>
   <OriginalElement>\DesignPatterns\More\Repository\PostRepository</OriginalElement>
   <nodes>
-    <node x="415.0" y="0.0">\DesignPatterns\More\Repository\Storage</node>
-    <node x="405.0" y="137.0">\DesignPatterns\More\Repository\MemoryStorage</node>
-    <node x="0.0" y="0.0">\DesignPatterns\More\Repository\Post</node>
-    <node x="0.0" y="373.0">\DesignPatterns\More\Repository\PostRepository</node>
+    <node x="283.0" y="167.0">\DesignPatterns\More\Repository\InMemoryPersistence</node>
+    <node x="0.0" y="0.0">\DesignPatterns\More\Repository\Domain\PostStatus</node>
+    <node x="590.0" y="385.0">\DesignPatterns\More\Repository\Domain\PostId</node>
+    <node x="0.0" y="385.0">\DesignPatterns\More\Repository\Domain\Post</node>
+    <node x="289.0" y="0.0">\DesignPatterns\More\Repository\Persistence</node>
+    <node x="320.0" y="385.0">\DesignPatterns\More\Repository\PostRepository</node>
   </nodes>
   <notes />
   <edges>
-    <edge source="\DesignPatterns\More\Repository\MemoryStorage" target="\DesignPatterns\More\Repository\Storage">
-      <point x="0.0" y="-74.5" />
-      <point x="0.0" y="43.5" />
+    <edge source="\DesignPatterns\More\Repository\InMemoryPersistence" target="\DesignPatterns\More\Repository\Persistence">
+      <point x="0.0" y="-81.0" />
+      <point x="0.0" y="58.5" />
     </edge>
   </edges>
-  <settings layout="Hierarchic Group" zoom="0.7394636015325671" x="299.5" y="251.0" />
-  <SelectedNodes />
+  <settings layout="Hierarchic Group" zoom="1.0" x="666.5" y="488.0" />
+  <SelectedNodes>
+    <node>\DesignPatterns\More\Repository\PostRepository</node>
+  </SelectedNodes>
   <Categories>
     <Category>Fields</Category>
     <Category>Constants</Category>

locale/ca/LC_MESSAGES/More/Repository/README.po

@@ -64,11 +64,11 @@ msgid "PostRepository.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:46
-msgid "Storage.php"
+msgid "Persistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:52
-msgid "MemoryStorage.php"
+msgid "InMemoryPersistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:59

locale/de/LC_MESSAGES/More/Repository/README.po

@@ -75,12 +75,12 @@ msgid "PostRepository.php"
 msgstr "PostRepository.php"
 
 #: ../../More/Repository/README.rst:46
-msgid "Storage.php"
-msgstr "Storage.php"
+msgid "Persistence.php"
+msgstr "Persistence.php"
 
 #: ../../More/Repository/README.rst:52
-msgid "MemoryStorage.php"
-msgstr "MemoryStorage.php"
+msgid "InMemoryPersistence.php"
+msgstr "InMemoryPersistence.php"
 
 #: ../../More/Repository/README.rst:59
 msgid "Test"

locale/es/LC_MESSAGES/More/Repository/README.po

@@ -64,11 +64,11 @@ msgid "PostRepository.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:46
-msgid "Storage.php"
+msgid "Persistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:52
-msgid "MemoryStorage.php"
+msgid "InMemoryPersistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:59

locale/pl/LC_MESSAGES/More/Repository/README.po

@@ -72,12 +72,12 @@ msgid "PostRepository.php"
 msgstr "PostRepository.php"
 
 #: ../../More/Repository/README.rst:46
-msgid "Storage.php"
-msgstr "Storage.php"
+msgid "Persistence.php"
+msgstr "Persistence.php"
 
 #: ../../More/Repository/README.rst:52
-msgid "MemoryStorage.php"
-msgstr "MemoryStorage.php"
+msgid "InMemoryPersistence.php"
+msgstr "InMemoryPersistence.php"
 
 #: ../../More/Repository/README.rst:59
 msgid "Test"

locale/pt_BR/LC_MESSAGES/More/Repository/README.po

@@ -72,11 +72,11 @@ msgid "PostRepository.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:46
-msgid "Storage.php"
+msgid "Persistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:52
-msgid "MemoryStorage.php"
+msgid "InMemoryPersistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:59

locale/ru/LC_MESSAGES/More/Repository/README.po

@@ -73,12 +73,12 @@ msgid "PostRepository.php"
 msgstr "PostRepository.php"
 
 #: ../../More/Repository/README.rst:46
-msgid "Storage.php"
-msgstr "Storage.php"
+msgid "Persistence.php"
+msgstr "Persistence.php"
 
 #: ../../More/Repository/README.rst:52
-msgid "MemoryStorage.php"
-msgstr "MemoryStorage.php"
+msgid "InMemoryPersistence.php"
+msgstr "InMemoryPersistence.php"
 
 #: ../../More/Repository/README.rst:59
 msgid "Test"

locale/zh_CN/LC_MESSAGES/More/Repository/README.po

@@ -64,11 +64,11 @@ msgid "PostRepository.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:46
-msgid "Storage.php"
+msgid "Persistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:52
-msgid "MemoryStorage.php"
+msgid "InMemoryPersistence.php"
 msgstr ""
 
 #: ../../More/Repository/README.rst:59