org.hibernate.validator.constraints not picking reloaded messages

Question

I am trying to use Spring's ReloadableResourceBundleMessageSource for LocalValidatorFactoryBean so that when I update an error message it should reflect without requiring the server to be restarted. I am using Spring 4.1.4, hibernate-validator 4.3.2.Final. Below are the code details -

context.xml -

<mvc:annotation-driven validator="validator" />
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
       <property name="basenames">  
        <list>  
            <value>file:../conf/fileapplication</value> <!-- Messages here will override the below properties file-->
            <value>/WEB-INF/application</value>
        </list>  
    </property>
    <property name="cacheSeconds" value="10"></property> <!-- Will check for refresh every 10 seconds -->
</bean>
<bean name="validator"
    class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean">
    <property name="validationMessageSource">
        <ref bean="messageSource"/>
    </property>
</bean>

Model -

import org.hibernate.validator.constraints.NotBlank;
public class InputForm {

@NotBlank ( message = "{required.string.blank}")
String requiredString;

Controller -

@RequestMapping(value = "/check/string", method = RequestMethod.POST)
public String checkString(
        @ModelAttribute("formModel") @Valid InputForm  inputForm ,
        BindingResult result, Model model, HttpServletResponse response,
        HttpServletRequest request) {
        if (result.hasErrors()) {
        model.addAttribute("formModel", inputForm);
        return "userInput";
        }
      // Do some backend validation with String
        result.reject("string.not.valid",
                "String is Invalid");
        model.addAttribute("formModel", inputForm);
        return "userInput";
}

application.properties (in /WEB_INF/ folder)

required.string.blank=Please enter the required string.
string.not.valid=Please enter a valid string.

fileapplication.properties (in /conf/ folder. Will override above file)

required.string.blank=You did not enter the required string. #Does not reflect when I change here
string.not.valid=You did not enter a valid string. #Reflects when I change here

Now the problem I am facing is, when I update "string.not.valid" in fileapplication.properties it reflects at runtime and I see the updated message. But when I update "required.string.blank" in fileapplication.properties it does not reflect at runtime. Note that the overriding part is working fine for both messages upon application start up. But the "reloading" part is not working fine for "required.string.blank".

Answer 1

This is what I figured out based on my research - We need to create our own MessageInterpolator and add it as dependency to the validator instead of message source. Because when we add a messageSource as dependency, it is cached by default by the validator and any message reloads spring does won't take effect in the validator's cached instance of messageSource.

Below are the details:

In context.xml, add the custom MessageInterpolator as dependency to LocalValidatorFactoryBean instead of messageSource:

<mvc:annotation-driven validator="validator" />
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
   <property name="basenames">  
    <list>  
        <value>file:../conf/fileapplication</value> <!-- Messages here will override the below properties file-->
        <value>/WEB-INF/application</value>
    </list>  
</property>
<property name="cacheSeconds" value="10"></property> <!-- Will check for refresh every 10 seconds -->
</bean>

<bean name="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean">
    <property name="messageInterpolator">
        <ref bean="messageInterpolator"/>
    </property>
</bean>

<bean name="messageInterpolator"
    class="com.my.org.support.MyCustomResourceBundleMessageInterpolator">
    <constructor-arg ref="messageSource" />
</bean>

Create your custom MessageInterpolator by extending Hibernate's org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator.

public class MyCustomResourceBundleMessageInterpolator extends
    ResourceBundleMessageInterpolator {
    public MyCustomResourceBundleMessageInterpolator(MessageSource messageSource)
    {
    // Passing false for the second argument 
    // in the super() constructor avoids the messages being cached.
    super(new MessageSourceResourceBundleLocator(messageSource), false);    
    }
}

Model, Controller and properties file can be same as in the question.