Singleton

THIS IS CONSIDERED TO BE AN ANTI-PATTERN! FOR BETTER TESTABILITY AND MAINTAINABILITY USE DEPENDENCY INJECTION!

Purpose

To have only one instance of this object in the application that will handle all calls.

DB Connector
Logger (may also be a Multiton if there are many log files for several purposes)
Lock file for the application (there is only one in the filesystem ...)

You can also find these code on GitHub

Singleton.php

.. literalinclude:: Singleton.php
   :language: php
   :linenos:

Tests/SingletonTest.php

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