title: get the size of a list in a property
body: <p>I have a class A which have a list of B elements.</p>
  
  <p>In my A class i would like to add:</p>
  
  <pre><code>int size;
  </code></pre>
  
  <p>which will be valued with the number of B elements. So when I would call <code>myA.getSize()</code> I will have it. </p>
  
  <p>Is it possible to map a count query with a single property in the hibernate mapping? </p>
  
  <p>I don't want to load the list that is why i would like to add a size property.</p>