Robware/base/DependencyInjector.php

<?php
class DependencyInjector {
	private $_dependencyArray=array();
	
	public function Register($interface,$class) {
		if (isset(class_implements($class)[$interface])){
			$this->_dependencyArray[$interface]=$class;
		}else
			throw new Exception("Class '$class' does not implement interface '$interface'");
	}
	
	public function Resolve($interface) {
		return new $this->_dependencyArray[$interface];
	}
}