Struts validation and XML Constants

["Krishna, Mattam (M.)" <mk...@ford.com>]

> <form-validation>
> 	<global>
> 		<constant>
> 			<constant-name>phone</constant-name>
> 			<constant-value>^\(?(\d{3})\)?[-| ]?(\d{3})[-|
> ]?(\d{4})$</constant-value>
> 		</constant>
> 	</global>
> 	<formset>
> 		<form name="checkoutForm">
> 			<field property="phone" depends="required,mask">
> 				<arg0
> key="registrationForm.firstname.displayname"/>
> 				<var>
> 					<var-name>mask</var-name>
> 					<var-value>${phone}</var-value>
> 				</var>
> 			</field>
> 		</form>
> 	</formset>
> </form-validation>
>  <ma...@ford.com> 
> What is the meaning of "^\(?(\d{3})\)?[-| ]?(\d{3})[-| ]?(\d{4})$" in
> the above code.?
> 
> Thanks and Regards,
> Krishna Mattam
> Team Member - CDF Toolset
> Contact:044-22548575
> Email: mkrish17@ford.com
> 
>