code: protected boolean validate(T obj) throws ParameterException {
      if(constraints != null) {
        for(ParameterConstraint<? super T> cons : this.constraints) {
          cons.test(obj);
        }
      }
      return true;
    }
docs: Validate a value after parsing (e.g. do constraint checks!)
  
  @param obj Object to validate
  @return true iff the object is valid for this parameter.
  @throws ParameterException when the object is not valid.