title: BeanValidation for runtime derived constraint values
body: <p>I would like to use jsr303 in place of current custom validation framework because of some features that the custom framework doesn't support yet, and I'm investigating if the jsr supports a certain usecase.</p>
  
  <p>Say I have a loan offer field presented to customer on some front-end, and the field is pre-populated with a loan amount generated by the system based on the user's credit score, and the customer is able to take the whole amount or lower than the offered value (so not more than what was offered).</p>
  
  <p>field:  </p>
  
  <pre><code>@DecimalMin("1000.00")
  @DecimalMax(onlyKnowAtRuntime)
  private BigDecimal loanOffer;
  
  offer = $20 000.00
  customer inputs = $50 000.00
  </code></pre>
  
  <p>Because the credit score is runtime generated, we don't know what the max (<code>@DecimalMax</code> which in this case is <code>$20 000.00</code>) value will be at compile time, but we need to make sure we validate that the customer doesn't take over <code>$20 000.00</code></p>
  
  <p>What ideas do you have around such a problem?</p>