title: Implementing observer pattern using WCF
body: <p>When I first posted this question I had strong coupling between my web service and application controller where the controller needed to open multiple threads to the service and as it received back data it had to do a lot of processing on the returned data and merge it into one dataset. I did not like the fact that the client had to so much processing and merge the returned data before it was ready to be used and wanted to move that layer to the service and let the service open the asynchronous threads to the suppliers and merge the results before returning them to the client.</p>
  
  <p>One challenge I had was that I could not wait till all threads were complete and results were merged, I had to start receiving data as it was available. That called me to implement an observer pattern on the service so that it would notify my application when new set of results are merged and ready to be used and send them to the application. </p>
  
  <p>I was looking for how to do this using either on ASMX webservices or WCF and so far I have found implementing it using WCF but this thread is always open for suggestions and improvements.</p>