Merge pull request #18 from Taluu/change-interface

Fixes #17 : Add a ChangeInterface

src/AbstractChange.php

@@ -17,7 +17,7 @@
  * @author Baptiste Clavié <[email protected]>
  * @author Rémy Gazelot <[email protected]>
  */
-abstract class AbstractChange
+abstract class AbstractChange implements ChangeInterface
 {
     /** old state */
     private $old;

src/ChangeInterface.php

@@ -0,0 +1,27 @@
+<?php
+/**
+ * This file is part of the Totem package
+ *
+ * For the full copyright and license information, please view the LICENSE file
+ * that was distributed with this source code.
+ *
+ * @copyright Baptiste Clavié <[email protected]>
+ * @license   http://www.opensource.org/licenses/MIT-License MIT License
+ */
+
+namespace Totem;
+
+/**
+ * Represent a change in a data, with both values (before and after it was modified)
+ *
+ * @author Baptiste Clavié <[email protected]>
+ */
+interface ChangeInterface
+{
+    /** @return mixed the data before it was changed */
+    public function getOld();
+
+    /** @return mixed the data after it was changed */
+    public function getNew();
+}
+