<?php
 
class DataBase
{
	public function name1()
	{
		echo 'db';
	}
}

class User
{
	protected $db;
 
	public function __construct(DataBase $DB)
	{
		$this->db = $DB;
	}
 
	public function name2(){
		$this->db->name1();
	}
}
 
 
$user = new User(new DataBase);
$user->name2();