source/core-developers/field-expression-validator-annotation.md

---
layout: default
title: FieldExpressionValidator Annotation
parent:
    title: Annotations
    url: annotations.html
---

# FieldExpressionValidator Annotation

This validator uses an OGNL expression to perform its validator. The error message will be added to the field if the expression 
returns false when it is evaluated against the value stack.

## Usage

The annotation must be applied at method level.

## Parameters

<p> <table class='confluenceTable' summary=''>
 <tr>
 <th class='confluenceTh'> Parameter </th>
 <th class='confluenceTh'> Required </th>
 <th class='confluenceTh'> Default </th>
 <th class='confluenceTh'> Notes </th>
 </tr>
 <tr>
 <td class='confluenceTd'>message</td>
 <td class='confluenceTd'>yes</td>
 <td class='confluenceTd'>&nbsp;</td>
 <td class='confluenceTd'>field error message</td>
 </tr>
 <tr>
 <td class='confluenceTd'>key</td>
 <td class='confluenceTd'>no</td>
 <td class='confluenceTd'>&nbsp;</td>
 <td class='confluenceTd'>i18n key from language specific properties file.</td>
 </tr>
 <tr>
 <td class='confluenceTd'>messageParams</td>
 <td class='confluenceTd'>no</td>
 <td class='confluenceTd'>&nbsp;</td>
 <td class='confluenceTd'>Additional params to be used to customize message - will be evaluated against the Value Stack</td>
 </tr>
 <tr>
 <td class='confluenceTd'>fieldName</td>
 <td class='confluenceTd'>no</td>
 <td class='confluenceTd'>&nbsp;</td>
 <td class='confluenceTd'>&nbsp;</td>
 </tr>
 <tr>
 <td class='confluenceTd'>shortCircuit</td>
 <td class='confluenceTd'>no</td>
 <td class='confluenceTd'>false</td>
 <td class='confluenceTd'>If this validator should be used as shortCircuit.</td>
 </tr>
 <tr>
 <td class='confluenceTd'> expression </td>
 <td class='confluenceTd'> yes </td>
 <td class='confluenceTd'>&nbsp;</td>
 <td class='confluenceTd'> An OGNL expression that returns a boolean value.  </td>
 </tr>
 </table>
</p>

## Examples

```java
 @FieldExpressionValidator(message = "Default message", key = "i18n.key", shortCircuit = true, expression = "an OGNL expression")

```