title: OSGi - Getting implementation for an interface
body: <p>Say I have an interface <code>Book</code> in my API bundle and some implementation <code>BookImpl</code> in my implementation bundle.  Generally, for singletons, I'd use the service registry to get my implementation.  For <code>Book</code>, however, I'd like to create a new instance every time I get the implementation.  </p>
  
  <p>What is the normal pattern for doing this in OSGi?  </p>
  
  <p>Would I have a service <code>BookCreator</code> with a method <code>createBook</code> that I get from the service registry and use to create my book instances?</p>