Agregada function para traer un campo de extraData

Entity/Traits/ExtraDataTrait.php

@@ -58,5 +58,21 @@ trait ExtraDataTrait
     {
         return $this->setExtraData(json_encode($extraData));
     }
+    
+    /**
+     * @param string $key
+     * 
+     * @return mixed
+     */
+    public function getData($key)
+    {
+        $extraData = $this->jsonExtraData();
+        $value = null;
+        if (isset($extraData[$key])) {
+            $value = $extraData[$key];
+        }
+        
+        return $value;
+    }
 
 }