Repository pattern

Repository/IStorage.php

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+<?php
+
+namespace DesignPatterns\Repository;
+
+/**
+ * Interface IStorage
+ *
+ * This interface describes methods for accessing storage.
+ * Concrete realization could be whatever we want - in memory, relational database, NoSQL database and etc
+ *
+ * @package DesignPatterns\Repository
+ */
+interface IStorage
+{
+    /**
+     * Method to persist data
+     * Returns new id for just persisted data
+     *
+     * @param array() $data
+     * @return int
+     */
+    public function persist($data);
+
+    /**
+     * Returns data by specified id.
+     * If there is no such data null is returned
+     *
+     * @param int $id
+     * @return array|null
+     */
+    public function retrieve($id);
+
+    /**
+     * Delete data specified by id
+     * If there is no such data - false returns, if data has been successfully deleted - true returns
+     *
+     * @param int $id
+     * @return bool
+     */
+    public function delete($id);
+}

Repository/MemoryStorage.php

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+<?php
+
+namespace DesignPatterns\Repository;
+
+/**
+ * Class MemoryStorage
+ * @package DesignPatterns\Repository
+ */
+class MemoryStorage implements IStorage
+{
+
+    private $data;
+    private $lastId;
+
+    public function __construct()
+    {
+        $this->data = array();
+        $this->lastId = 0;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function persist($data)
+    {
+        $this->data[++$this->lastId] = $data;
+        return $this->lastId;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function retrieve($id)
+    {
+        return isset($this->data[$id]) ? $this->data[$id] : null;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function delete($id)
+    {
+        if(!isset($this->data[$id])){
+            return false;
+        }
+
+        $this->data[$id] = null;
+        unset($this->data[$id]);
+
+        return true;
+    }
+
+}
+

Repository/Post.php

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+<?php
+
+namespace DesignPatterns\Repository;
+/**
+ * Post represents entity for some post that user left on the site
+ *
+ * Class Post
+ * @package DesignPatterns\Repository
+ */
+class Post
+{
+    /**
+     * @var int
+     */
+    private $id;
+
+    /**
+     * @var string
+     */
+    private $title;
+
+    /**
+     * @var string
+     */
+    private $text;
+
+    /**
+     * @var string
+     */
+    private $author;
+
+    /**
+     * @var \DateTime
+     */
+    private $created;
+
+
+
+
+    /**
+     * @param int $id
+     */
+    public function setId($id)
+    {
+        $this->id = $id;
+    }
+
+    /**
+     * @return int
+     */
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * @param string $author
+     */
+    public function setAuthor($author)
+    {
+        $this->author = $author;
+    }
+
+    /**
+     * @return string
+     */
+    public function getAuthor()
+    {
+        return $this->author;
+    }
+
+    /**
+     * @param \DateTime $created
+     */
+    public function setCreated($created)
+    {
+        $this->created = $created;
+    }
+
+    /**
+     * @return \DateTime
+     */
+    public function getCreated()
+    {
+        return $this->created;
+    }
+
+    /**
+     * @param string $text
+     */
+    public function setText($text)
+    {
+        $this->text = $text;
+    }
+
+    /**
+     * @return string
+     */
+    public function getText()
+    {
+        return $this->text;
+    }
+
+    /**
+     * @param string $title
+     */
+    public function setTitle($title)
+    {
+        $this->title = $title;
+    }
+
+    /**
+     * @return string
+     */
+    public function getTitle()
+    {
+        return $this->title;
+    }
+
+
+
+}

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());
+    }
+}

Repository/README.md

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+# Repository
+
+## Purpose
+
+Mediates between the domain and data mapping layers using a collection-like interface for accessing domain objects.
+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.
+
+## Examples
+
+* Doctrine 2 ORM: there is Repository that mediates between Entity and DBAL and contains methods to retrieve objects
+* Laravel Framework