Encapsulate varying behavior for the same routine based on an object's state. This can be a cleaner way for an object to change its behavior at runtime without resorting to large monolithic conditional statements.

You can also find this code on GitHub

OrderContext.php

.. literalinclude:: OrderContext.php
   :language: php
   :linenos:

State.php

.. literalinclude:: State.php
   :language: php
   :linenos:

StateCreated.php

.. literalinclude:: StateCreated.php
   :language: php
   :linenos:

StateShipped.php

.. literalinclude:: StateShipped.php
   :language: php
   :linenos:

StateDone.php

.. literalinclude:: StateDone.php
   :language: php
   :linenos:

Tests/StateTest.php

.. literalinclude:: Tests/StateTest.php
   :language: php
   :linenos: