Java Bean Validation (JSR303) constraints involving relationship between several bean properties

Question

Say I have the following simple java bean:

class MyBean {
   private Date startDate;
   private Date endDate;
   //setter, getters etc...
}

Answer 1

If you're using Hibernate Validator in version 4.1 or later you can use the @ScriptAssert constraint together with a scripting or expression language to express this kind of constraint. Using JavaScript your example would look like this:

 @ScriptAssert(lang = "javascript", script = "_this.startDate.before(_this.endDate)")
 public class CalendarEvent {

      private Date startDate;

      private Date endDate;

      //...
 } 

You can get an even more compact syntax by creating a custom constraint for the script language of your choice:

@JexlAssert("_.startDate < _.endDate")
public class CalendarEvent {

    private Date startDate;

    private Date endDate;

    //...
}