Custom Annotation using JSR 3.0

Question

I have one pojo class with name LoanForm with few fields:String loanType;String source;String amount;

I created a custom annotation for loanType. Below is the code.Next I created another class as validator LoanTypeConstraintValidator. Below is the code.The above annotation is checking if loantype is blank or not. I have 3 sources let's say A,B,C. Now if source is A and user submits the form an error message will get display. But if source is B even if loanType is null or blank form should get submitted. So I am stuck at how to access source field in this LoanType custom annotation and how to check if source is A or B or C.

Here is my Custom Validator class code:

 public class LoanTypeConstraintValidator
            implements ConstraintValidator<LoanType, Integer>
    {
        public void initialize(LoanType loanType)
        {
        }
        @Override
        public boolean isValid(Integer loanTypeField, ConstraintValidatorContext arg1)
        {
            if (loanTypeField == null)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }