merapi | Multi-purpose Dependency Injection Container | Dependency Injection library

For the most part your code works fine however there are a few minor things here to take care of and others to consider. Let's start with the Pengiriman class.

In your Pengiriman class you have a typical constructor which accepts no parameters and within that constructor you default all class member variables to either 0 or Null String (""). You can eliminate this additional code if you merely initialize your variables where declared. This would make those values default whenever a new instance of Pengiriman is created, for example: