<?php

class DatabaseConnection {

	/** @var  string */
	protected $host;

	/** @var  string */
	protected $user;

	/** @var  string */
	protected $password;

...

	/**
	 * @param string $host
	 * @param string $user
	 * @param string $password
	 */
	public function __construct($host, $user, $password, ...) {
		$this->host = $host;
		$this->user = $user;
		$this->password = $password;
		...
	}

...
}

class UserFacade {

	/** @var  DatabaseConnection */
	protected $databaseConnection;

	/**
	 * @param DatabaseConnection $databaseConnection
	 */
	public function __construct(DatabaseConnection $databaseConnection) {
		$this->databaseConnection = $databaseConnection;
	}

	/**
	 * @return array
	 */
	public function getUsers() {
		$results = $this->databaseConnection->query('SELECT name FROM user');

		sort($results);

		return $results;
	}
}