Design pattern stratégie (http://kandran.fr/design-pattern-strategie/)

ApplicationA.php

<?php

require_once("ApplicationInterface.php");

class ApplicationA implements ApplicationInterface{
	public function run()
	{
		echo "<br/> Application A start running";
		//some computation
		echo "<br/> Application A finished";
	}	
}

ApplicationB.php

<?php

require_once("ApplicationInterface.php");

class ApplicationB implements ApplicationInterface{
	public function run()
	{
		echo "<br/> Application B start running";
		//some other computation
		echo "<br/> Application B finished";	
	}	
}

ApplicationInterface.php

<?php

interface ApplicationInterface
{
    public function run();
}

ApplicationStarter.php

<?php

require_once("ApplicationInterface.php");

class ApplicationStarter{
	public function startApplication(ApplicationInterface $application)
	{
		$application->run(); //here we don't know the class name of application
	}
}

index.php

<?php

require_once("ApplicationA.php");
require_once("ApplicationB.php");
require_once("ApplicationStarter.php");

$applicationStarterObject = new ApplicationStarter();
$application1 = new ApplicationA();
$application2 = new ApplicationB();
$application3 = new ApplicationA();

$applicationsToRun = array($application1, $application2 , $application3);

foreach($applicationsToRun as $application){
	$applicationStarterObject->startApplication($application);
}