title: Aggregate exceptions
body: <p>I'm often finding the need to validate a set of conditions, and instead of failing early (returning false or throwing an exception when the first condition is not fulfilled), I need to aggregate the results and report the individual failures.</p>
  
  <p>I'm currently either using a list with custom entries (basically an entry consists of the type of the failure and some informative message) or some kind of observer (which also just aggregates the failures), but I have a feeling that this should be a common problem and that there should be some existing pattern for solving this.</p>