Repository pattern

Repository/PostRepository.php

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+<?php
+
+namespace DesignPatterns\Repository;
+
+/**
+ * Repository for class Post
+ * This class is between Entity layer(class Post) and access object layer(interface IStorage)
+ * 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
+ * Repository also supports the objective of achieving a clean separation and one-way dependency between the domain and data mapping layers
+ *
+ * Class PostRepository
+ * @package DesignPatterns\Repository
+ */
+class PostRepository
+{
+    private $persistence;
+
+    public function __construct(IStorage $persistence)
+    {
+        $this->persistence = $persistence;
+    }
+
+    /**
+     * Returns Post object by specified id
+     *
+     * @param int $id
+     * @return Post|null
+     */
+    public function getById($id)
+    {
+        $arrayData = $this->persistence->retrieve($id);
+        if(is_null($arrayData)){
+            return null;
+        }
+
+        $post = new Post();
+        $post->setId($arrayData['id']);
+        $post->setAuthor($arrayData['author']);
+        $post->setCreated($arrayData['created']);
+        $post->setText($arrayData['text']);
+        $post->setTitle($arrayData['title']);
+
+        return $post;
+    }
+
+    /**
+     * Save post object and populate it with id
+     *
+     * @param Post $post
+     * @return Post
+     */
+    public function save(Post $post)
+    {
+        $id = $this->persistence->persist(array(
+            'author' => $post->getAuthor(),
+            'created' => $post->getCreated(),
+            'text' => $post->getText(),
+            'title' => $post->getTitle()
+        ));
+
+        $post->setId($id);
+        return $post;
+    }
+
+    /**
+     * Deletes specified Post object
+     *
+     * @param Post $post
+     * @return bool
+     */
+    public function delete(Post $post)
+    {
+        return $this->persistence->delete($post->getId());
+    }
+}