How do i get a field value inside a custom Struts Validator, when the field's type is FormFile?

String value = ValidatorUtils.getValueAsString(bean,field.getProperty());

FormFile myFile = (FormFile) // TODO

<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_2.dtd">
<struts-config>
    <form-beans>
    	<form-bean name="ChangePictureForm" type="struts.administration.ChangePictureForm">
    		<form-property name="id" type="java.lang.String" />
    		<form-property name="file" type="org.apache.struts.upload.FormFile" />
        </form-bean>
    </form-beans>
...
..
.

<!-- User Custom Validation Rules -->
    <validator name="size"
        	classname="struts.StrutsValidator"
        	method="validateSize"
        	methodParams="java.lang.Object,
    					org.apache.commons.validator.Validator,
    					org.apache.commons.validator.ValidatorAction,
    					org.apache.commons.validator.Field,
    					org.apache.struts.action.ActionMessages,
    					javax.servlet.http.HttpServletRequest"
        	depends=""
        	msg="errors.size"/>

package struts;

import javax.servlet.http.HttpServletRequest;
import org.apache.commons.validator.Field;
import org.apache.commons.validator.Validator;
import org.apache.commons.validator.ValidatorAction;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.upload.FormFile;
import org.apache.struts.validator.Resources;

public class StrutsValidator {
    public static boolean validateSize (
    		Object bean,
    		Validator validator,
    		ValidatorAction validatorAction,
    		Field field,
    		ActionMessages errors,
    		HttpServletRequest request) {

    	 FormFile myFile = null; //TODO (FormFile) get it from somewhere

    	String type = field.getVarValue("type");
    	int size = myFile.getFileSize();

    	// MySQL Storage Requirements http://dev.mysql.com/doc/refman/5.0/en/storage-requirements.html
    	int allowed_size = 65538; //Blob L + 2 bytes, where L <  2 ^ 16
    	if(type.equalsIgnoreCase("tinyblob")) {
    		allowed_size = 257; // L + 1 bytes, where L <  2 ^ 8
    	} else if(type.equalsIgnoreCase("mediumblog")) {
    		allowed_size = 16777219; // 16 Mb - L + 3 bytes, where L <  2 ^ 24
    	} else if(type.equalsIgnoreCase("longblob")) {
    		allowed_size = 16777219; // 4096 Mb - L + 4 bytes, where L <  2 ^ 32
    	}
    	try {
    		if(size>=allowed_size) {
    			errors.add(field.getKey(),Resources.getActionMessage(validator,request,validatorAction,field));
    			return false;
    		}
    	} catch (Exception e) {
    			errors.add(field.getKey(),Resources.getActionMessage(validator,request,validatorAction,field));
    			return false;
    	}
    	return true;
    }
}

<!DOCTYPE form-validation PUBLIC "-//Apache Software Foundation//DTD Commons Validator Rules Configuration 1.0//EN" "http://jakarta.apache.org/commons/dtds/validator_1_3_0.dtd">
<form-validation>
    <formset>
    <form name="ChangePictureForm">
    	 <field property="file" depends="required,size">
    		<arg0 key="file" />
            <arg1 name="type" key="${var:type}" resource="false" />
            <var>
               <var-name>type</var-name>
               <var-value>blob</var-value>
            </var>
         </field>
     </form>
    </formset>
</form-validation>