PHP7 DataMapper

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);
     }
 }