Expert Spring MVC and Web Flow

Listing 9-22.rejectValue() Methods in the org.springframework.validation.Errors Interface

public void rejectValue(String propertyName, String errorCode);

public void rejectValue(String propertyName, String errorCode, ➥

String defaultMessage);

public void rejectValue(String propertyName, String errorCode, Object[] ➥

errorArguments, String defaultMessage);

Rejecting a property value is called a field error. Types of field errors include invalid values

of any kind, nullvalues for required properties, and Stringvalues containing only white-space

characters.

Global errors typically appear on top of a form in the view, while field errors typically

appear next to the input fields they are related to.

The Errorsinterface supports nested Validators. This allows you to reuse Validators for a

single class to validate object graphs. Two methods on the Errorsinterface allow you to man-

age the nested path. The nested path defines the path to the object that is rejected (or its

property values).

CustomerValidatordispatches control to the AddressValidatorto validate the address prop-

erty. Before delegating, the CustomerValidatorchanges the nested path. Refer to Listing 9-23.

Listing 9-23.Example of Using Nested Path to Delegate to Other Validator

package com.apress.expertspringmvc.validation;

import org.springframework.validation.Validator;

import org.springframework.validation.Errors;

import com.apress.expertspringmvc.Customer;

import org.apache.commons.lang.StringUtils;

public class CustomerValidator implements Validator {

public boolean supports(Class clazz) {

return Customer.class.isAssignableFrom(clazz);

}

public void validate(Object target, Errors errors) {

Customer customer = (Customer)target;

// other constraint checks

errors.pushNestedPath("address");

getAddressValidator(customer.getAddress(), errors);

errors.popNestedPath();

}

private Validator addressValidator = null;

public void setAddressValidator(Validator addressValidator) {

this.addressValidator = addressValidator;

}

private Validator getAddressValidator() {

if (this.addressValidator = null) {

throw new IllegalStateException("Address validator is not available");

280 CHAPTER 9 ■VALIDATION