Configuration.php

<?php

namespace DesignPatterns\DependencyInjection;

/**
 * Dependency Injection
 *
 * Purpose:
 * to implement a loosely coupled architecture in order to get better testable, maintainable and extendable code
 * 
 * Examples:
 * - the Doctrine2 ORM uses dependency injection e.g. for Configuration that is injected into a Connection object. for
 *   testing purposes, one can easily create a mock object of the configuration and inject that into the connection
 *   object
 * - Symfony and Zend Framework 2 already have containers for DI that create objects via a configuration array and
 *   inject them where needed (i.e. in Controllers)
 *
 */
class Configuration
{
    /**
     * @var string
     */
    protected $host;

    /**
     * @param string $host
     *
     * @return Configuration
     */
    public function setHost($host)
    {
        $this->host = $host;

        return $this; // for a fluent interface
    }

    /**
     * @return string
     */
    public function getHost()
    {
        return $this->host;
    }
}