title: Does Interface Symbol Show Data Transfer Direction
body: <p>I am trying to understand UML Component diagrams but I am confused about the direction of ball and socket symbols for interfaces. I am not completely sure what the direction of the ball and socket exactly represents.</p>
  <p>On some sources it says that it shows material input/output direction. The component with ball provides data through an interface to the component with the socket.</p>
  <p>On some other sources it says that it shows which one provides the interface and which one uses it. The component with the ball implements the interface while the component with the socket uses it.</p>
  <p>So which explanation is more accurate?</p>