OmniFaces Showcase

Unlike native JSF validation error messages, in a bean validation message by default the label of the component where a validation constraint violation originated from can not be displayed in the middle of a message. Using the javax.faces.validator.BeanValidator.MESSAGE bundle key such label can be put in front or behind the message, but that's it. With this JsfLabelMessageInterpolator a label can appear in the middle of a message, by using the special placeholder {jsf.label} in bean validation messages.

Note that Bean Validation is not only called from within JSF, and as such JSF might not be available. If JSF is not available occurrences of {jsf.label} will be replaced by an empty string. The user should take care that messages are compatible with both situations if needed.

This message interpolator is not needed for putting a component label before or after a bean validation message. That functionality is already provided by JSF itself via the javax.faces.validator.BeanValidator.MESSAGE key in any resource bundle known to JSF.

Installation

Create a /META-INF/validation.xml file in WAR with the following contents:

<?xml version="1.0" encoding="UTF-8"?>
<validation-config
    xmlns="http://jboss.org/xml/ns/javax/validation/configuration"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://jboss.org/xml/ns/javax/validation/configuration validation-configuration-1.0.xsd"
>
    <message-interpolator>org.omnifaces.validator.JsfLabelMessageInterpolator</message-interpolator>
</validation-config>

Usage

As an example, the customization of @Size in ValidationMessages.properties:

javax.validation.constraints.Size.message = The size of {jsf.label} must be between {min} and {max} characters

<p>
    Enter more than 2 resp. 3 characters in the input fields below and press submit to trigger 
    a validation error. Note how the field's label appears in the message, which originates from
    <code>ValidationMessages.properties</code>.
</p>

<h:form>
    <h:messages />
    
    <h:panelGrid columns="2">
        <o:outputLabel for="foo" value="Foo" />
        <h:inputText id="foo" value="#{validateConstraintsBean.constrainedEntity.foo}" />

        <o:outputLabel for="bar" value="Bar" />
        <h:inputText id="bar" value="#{validateConstraintsBean.constrainedEntity.bar}" />
        
        <h:commandButton value="submit">
            <f:ajax execute="@form" render="@form" />
        </h:commandButton>
        
    </h:panelGrid>
    
</h:form>

package org.omnifaces.showcase.validators;

import javax.inject.Named;

import org.omnifaces.showcase.model.ConstrainedEntity;

@Named
public class ValidateConstraintsBean {

    private ConstrainedEntity constrainedEntity = new ConstrainedEntity();

    public ConstrainedEntity getConstrainedEntity() {
        return constrainedEntity;
    }

}

package org.omnifaces.showcase.model;

import javax.validation.constraints.Size;

public class ConstrainedEntity {
    
    @Size(min = 0, max = 2)
    public String foo;
    
    @Size(min = 0, max = 3)
    public String bar;

    public String getFoo() {
        return foo;
    }

    public void setFoo(String foo) {
        this.foo = foo;
    }

    public String getBar() {
        return bar;
    }

    public void setBar(String bar) {
        this.bar = bar;
    }
    
    

}

javax.validation.constraints.Size.message = The size of {jsf.label} must be between {min} and {max} characters.