java.lang.Object
   com.opensymphony.xwork2.validator.validators.ValidatorSupport
      com.opensymphony.xwork2.validator.validators.FieldValidatorSupport
         com.opensymphony.xwork2.validator.validators.FieldExpressionValidator

All Implemented Interfaces:
    FieldValidator, ShortCircuitableValidator, Validator

• fieldName - The field name this validator is validating. Required if using Plain-Validator Syntax otherwise not required
• expression - The Ognl expression (must evaluate to a boolean) which is to be evalidated the stack

<!-- Plain Validator Syntax -->
<validators>
<!-- Plain Validator Syntax -->
<validator type="fieldexpression">
<param name="fieldName">myField</param>
<param name="expression"><![CDATA[#myCreditLimit > #myGirfriendCreditLimit]]></param>
<message>My credit limit should be MORE than my girlfriend</message>
<validator>

<!-- Field Validator Syntax -->
<field name="myField">
<field-validator type="fieldexpression">
<param name="expression"><![CDATA[#myCreditLimit > #myGirfriendCreditLimit]]></param>
<message>My credit limit should be MORE than my girlfriend</message>
</field-validator>
</field>

</vaidators>

author: $ - Author: mrdon $

version: $ - Revision: 1063 $

 public String getExpression() 
{
        return expression;
}

 public  void setExpression(String expression) 
{
        this.expression = expression;
}

 public  void validate(Object object) throws ValidationException 
{
        String fieldName = getFieldName();
        Boolean answer = Boolean.FALSE;
        Object obj = null;
        try {
            obj = getFieldValue(expression, object);
        } catch (ValidationException e) {
            throw e;
        } catch (Exception e) {
            // let this pass, but it will be logged right below
        }
        if ((obj != null) && (obj instanceof Boolean)) {
            answer = (Boolean) obj;
        } else {
            log.warn("Got result of " + obj + " when trying to get Boolean.");
        }
        if (!answer.booleanValue()) {
            addFieldError(fieldName, object);
        }
}