title: Get count of items in Google Cloud Datastore
body: <p>Using app engine's <code>endpoints</code> in my android app I need to get the number of items in the data store based on a filter and return that to my app.</p>
  
  <p>I could do on app engine and then return the results as a collection but I dont need any of that data and just need the number of items.</p>
  
  <p>What would be the appropriate was to achieve this using the Java API since I cannot return primitive types?</p>