PHP7 DataMapper

Structural/DataMapper/README.rst

@@ -47,6 +47,12 @@ UserMapper.php
    :language: php
    :linenos:
 
+StorageAdapter.php
+
+.. literalinclude:: StorageAdapter.php
+    :language: php
+    :linenos:
+
 Test
 ----
 

Structural/DataMapper/StorageAdapter.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace DesignPatterns\Structural\DataMapper;
+
+class StorageAdapter
+{
+    /**
+     * @var array
+     */
+    private $data = [];
+
+    public function __construct(array $data)
+    {
+        $this->data = $data;
+    }
+
+    /**
+     * @param int $id
+     *
+     * @return array|null
+     */
+    public function find(int $id)
+    {
+        if (isset($this->data[$id])) {
+            return $this->data[$id];
+        }
+
+        return null;
+    }
+}

Structural/DataMapper/Tests/DataMapperTest.php

@@ -2,109 +2,29 @@
 
 namespace DesignPatterns\Structural\DataMapper\Tests;
 
-use DesignPatterns\Structural\DataMapper\User;
+use DesignPatterns\Structural\DataMapper\StorageAdapter;
 use DesignPatterns\Structural\DataMapper\UserMapper;
 
-/**
- * UserMapperTest tests the datamapper pattern.
- */
 class DataMapperTest extends \PHPUnit_Framework_TestCase
 {
-    /**
-     * @var UserMapper
-     */
-    protected $mapper;
-
-    /**
-     * @var DBAL
-     */
-    protected $dbal;
-
-    protected function setUp()
+    public function testCanMapUserFromStorage()
     {
-        $this->dbal = $this->getMockBuilder('DesignPatterns\Structural\DataMapper\DBAL')
-                ->disableAutoload()
-                ->setMethods(array('insert', 'update', 'find', 'findAll'))
-                ->getMock();
+        $storage = new StorageAdapter([1 => ['username' => 'domnikl', 'email' => 'liebler.dominik@gmail.com']]);
+        $mapper = new UserMapper($storage);
 
-        $this->mapper = new UserMapper($this->dbal);
-    }
+        $user = $mapper->findById(1);
 
-    public function getNewUser()
-    {
-        return array(array(new User(null, 'Odysseus', 'Odysseus@ithaca.gr')));
-    }
-
-    public function getExistingUser()
-    {
-        return array(array(new User(1, 'Odysseus', 'Odysseus@ithaca.gr')));
-    }
-
-    /**
-     * @dataProvider getNewUser
-     */
-    public function testPersistNew(User $user)
-    {
-        $this->dbal->expects($this->once())
-                ->method('insert');
-        $this->mapper->save($user);
-    }
-
-    /**
-     * @dataProvider getExistingUser
-     */
-    public function testPersistExisting(User $user)
-    {
-        $this->dbal->expects($this->once())
-                ->method('update');
-        $this->mapper->save($user);
-    }
-
-    /**
-     * @dataProvider getExistingUser
-     */
-    public function testRestoreOne(User $existing)
-    {
-        $row = array(
-            'userid' => 1,
-            'username' => 'Odysseus',
-            'email' => 'Odysseus@ithaca.gr',
-        );
-        $rows = new \ArrayIterator(array($row));
-        $this->dbal->expects($this->once())
-                ->method('find')
-                ->with(1)
-                ->will($this->returnValue($rows));
-
-        $user = $this->mapper->findById(1);
-        $this->assertEquals($existing, $user);
-    }
-
-    /**
-     * @dataProvider getExistingUser
-     */
-    public function testRestoreMulti(User $existing)
-    {
-        $rows = array(array('userid' => 1, 'username' => 'Odysseus', 'email' => 'Odysseus@ithaca.gr'));
-        $this->dbal->expects($this->once())
-                ->method('findAll')
-                ->will($this->returnValue($rows));
-
-        $user = $this->mapper->findAll();
-        $this->assertEquals(array($existing), $user);
+        $this->assertInstanceOf('DesignPatterns\Structural\DataMapper\User', $user);
     }
 
     /**
      * @expectedException \InvalidArgumentException
-     * @expectedExceptionMessage User #404 not found
      */
-    public function testNotFound()
+    public function testWillNotMapInvalidData()
     {
-        $this->dbal->expects($this->once())
-                ->method('find')
-                ->with(404)
-                ->will($this->returnValue(array()));
+        $storage = new StorageAdapter([]);
+        $mapper = new UserMapper($storage);
 
-        $user = $this->mapper->findById(404);
+        $mapper->findById(1);
     }
 }

Structural/DataMapper/User.php

@@ -2,56 +2,34 @@
 
 namespace DesignPatterns\Structural\DataMapper;
 
-/**
- * DataMapper pattern.
- *
- * This is our representation of a DataBase record in the memory (Entity)
- *
- * Validation would also go in this object
- */
 class User
 {
     /**
-     * @var int
+     * @var string
      */
-    protected $userId;
+    private $username;
 
     /**
      * @var string
      */
-    protected $username;
+    private $email;
 
-    /**
-     * @var string
-     */
-    protected $email;
-
-    /**
-     * @param null $id
-     * @param null $username
-     * @param null $email
-     */
-    public function __construct($id = null, $username = null, $email = null)
+    public static function fromState(array $state): User
     {
-        $this->setUserID($id);
-        $this->setUsername($username);
-        $this->setEmail($email);
+        // validate state before accessing keys!
+
+        return new self(
+            $state['username'],
+            $state['email']
+        );
     }
 
-    /**
-     * @return int
-     */
-    public function getUserId()
+    public function __construct(string $username, string $email)
     {
-        return $this->userId;
-    }
+        // validate parameters before setting them!
 
-    /**
-     * @param int $userId
-     */
-    public function setUserID($userId)
-    {
-        $this->userId = $userId;
+        $this->username = $username;
+        $this->email = $email;
     }
 
     /**
@@ -62,14 +40,6 @@ class User
         return $this->username;
     }
 
-    /**
-     * @param string $username
-     */
-    public function setUsername($username)
-    {
-        $this->username = $username;
-    }
-
     /**
      * @return string
      */
@@ -77,12 +47,4 @@ class User
     {
         return $this->email;
     }
-
-    /**
-     * @param string $email
-     */
-    public function setEmail($email)
-    {
-        $this->email = $email;
-    }
 }

Structural/DataMapper/UserMapper.php

@@ -2,107 +2,44 @@
 
 namespace DesignPatterns\Structural\DataMapper;
 
-/**
- * class UserMapper.
- */
 class UserMapper
 {
     /**
-     * @var DBAL
+     * @var StorageAdapter
      */
-    protected $adapter;
+    private $adapter;
 
     /**
-     * @param DBAL $dbLayer
+     * @param StorageAdapter $storage
      */
-    public function __construct(DBAL $dbLayer)
+    public function __construct(StorageAdapter $storage)
     {
-        $this->adapter = $dbLayer;
+        $this->adapter = $storage;
     }
 
     /**
-     * saves a user object from memory to Database.
-     *
-     * @param User $user
-     *
-     * @return bool
-     */
-    public function save(User $user)
-    {
-        /* $data keys should correspond to valid Table columns on the Database */
-        $data = array(
-            'userid' => $user->getUserId(),
-            'username' => $user->getUsername(),
-            'email' => $user->getEmail(),
-        );
-
-        /* if no ID specified create new user else update the one in the Database */
-        if (null === ($id = $user->getUserId())) {
-            unset($data['userid']);
-            $this->adapter->insert($data);
-
-            return true;
-        } else {
-            $this->adapter->update($data, array('userid = ?' => $id));
-
-            return true;
-        }
-    }
-
-    /**
-     * finds a user from Database based on ID and returns a User object located
-     * in memory.
+     * finds a user from storage based on ID and returns a User object located
+     * in memory. Normally this kind of logic will be implemented using the Repository pattern.
+     * However the important part is in mapRowToUser() below, that will create a business object from the
+     * data fetched from storage
      *
      * @param int $id
      *
-     * @throws \InvalidArgumentException
-     *
      * @return User
      */
-    public function findById($id)
+    public function findById(int $id): User
     {
         $result = $this->adapter->find($id);
 
-        if (0 == count($result)) {
+        if ($result === null) {
             throw new \InvalidArgumentException("User #$id not found");
         }
-        $row = $result->current();
 
-        return $this->mapObject($row);
+        return $this->mapRowToUser($result);
     }
 
-    /**
-     * fetches an array from Database and returns an array of User objects
-     * located in memory.
-     *
-     * @return array
-     */
-    public function findAll()
+    private function mapRowToUser(array $row): User
     {
-        $resultSet = $this->adapter->findAll();
-        $entries = array();
-
-        foreach ($resultSet as $row) {
-            $entries[] = $this->mapObject($row);
-        }
-
-        return $entries;
-    }
-
-    /**
-     * Maps a table row to an object.
-     *
-     * @param array $row
-     *
-     * @return User
-     */
-    protected function mapObject(array $row)
-    {
-        $entry = new User();
-        $entry->setUserID($row['userid']);
-        $entry->setUsername($row['username']);
-        $entry->setEmail($row['email']);
-
-        return $entry;
+        return User::fromState($row);
     }
 }

Structural/DataMapper/uml/DataMapper.uml

@@ -1,23 +1,23 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<Diagram>
-  <ID>PHP</ID>
-  <OriginalElement>\DesignPatterns\Structural\DataMapper\User</OriginalElement>
-  <nodes>
-    <node x="0.0" y="0.0">\DesignPatterns\Structural\DataMapper\User</node>
-    <node x="0.0" y="274.0">\DesignPatterns\Structural\DataMapper\UserMapper</node>
-  </nodes>
-  <notes />
-  <edges />
-  <settings layout="Hierarchic Group" zoom="0.871331828442438" x="141.5" y="211.5" />
-  <SelectedNodes>
-    <node>\DesignPatterns\Structural\DataMapper\User</node>
-  </SelectedNodes>
-  <Categories>
-    <Category>Fields</Category>
-    <Category>Constants</Category>
-    <Category>Constructors</Category>
-    <Category>Methods</Category>
-  </Categories>
-  <VISIBILITY>private</VISIBILITY>
-</Diagram>
-
+<?xml version="1.0" encoding="UTF-8"?>
+<Diagram>
+  <ID>PHP</ID>
+  <OriginalElement>\DesignPatterns\Structural\DataMapper\StorageAdapter</OriginalElement>
+  <nodes>
+    <node x="0.0" y="185.0">\DesignPatterns\Structural\DataMapper\UserMapper</node>
+    <node x="204.0" y="185.0">\DesignPatterns\Structural\DataMapper\StorageAdapter</node>
+    <node x="0.0" y="0.0">\DesignPatterns\Structural\DataMapper\User</node>
+  </nodes>
+  <notes />
+  <edges />
+  <settings layout="Hierarchic Group" zoom="1.0" x="64.0" y="88.5" />
+  <SelectedNodes>
+    <node>\DesignPatterns\Structural\DataMapper\StorageAdapter</node>
+  </SelectedNodes>
+  <Categories>
+    <Category>Methods</Category>
+    <Category>Fields</Category>
+    <Category>Constants</Category>
+  </Categories>
+  <VISIBILITY>private</VISIBILITY>
+</Diagram>
+