title: Conditional saveOrUpdate in hibernate
body: <p>I have a mapped class that has a date property. I would like to saveOrUpdate objects of this class so that already existing is updated only if it is older than the stored one.</p>
  
  <p>How would I do that (neatly and efficiently if possible)?</p>
  
  <p>I have a lot of classes like this so I would hope to avoid writing tons of custom HQL for all of them.</p>