title: Separation of Presentation layer from Business layer
body: <p>From an article i just read, </p>
  
  <p><a href="https://stackoverflow.com/questions/424675/ui-layer-abstraction">UI Layer Abstraction</a></p>
  
  <p>Well are there any setbacks to a full separation between the presentation layer and the business layer?</p>
  
  <p>This question actually came from a problem of tracing the progress of a process (certain series of instructions) and updating a progress bar accordingly for example.</p>
  
  <p>Now the only one who knows the actual progress is the process itself, and that is in the business layer. So if both layers are pretty separate, how can I reach the progress bar from within the business layer without stepping on the presentation layer's domain? Or at least return progress values to the presentation layer?</p>