JSF form validation with AJAX and validator class [duplicate] - ajax

Question

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How to perform JSF validation in actionListener or action method?
(5 answers)
Closed 3 years ago.
I have an assignment for university where we shall validate form input with AJAX and a Validator Class. Now, I have used AJAX in JSF for filtering a list. But I don't know how to combine it with a validator. The validation should happen when user leaves input field. The validator should check if email input matches a regex pattern and if there is an existing user with the same email. If validation fails, a FacesMessage should be shown. How do I connect the dots?
This is part of a bigger project and I have tried to include only the relevant code.
FILE STRUCTURE (only relevant part)
.
├── java
│ ├── dao
│ ├── logic
│ ├── presentation
│ │ ├── managedbeans
│ │ │ └── UserBean.java
│ │ └── validator
│ │ └── Email.java
│ │
│ └── transfer
└── webapp
└── signup.xhtml
THE CODE
signup.xhtml only relevant part of the form
<h:form id="registerForm" class="col l6 s12 center">
<h:outputLabel for="eMail" value="Email" class="active" />
<h:inputText
id="eMail"
value="#{user.email}"
class="validate"
requiredMessage="Email is required"
label="eMail"
maxlength="25"
alt="email"
autocomplete="on"
required="true">
<f:validator validatorId="emailValidator"/>
<f:ajax event="change" listener="#{user.validateEmail}" execute="eMail" render="emailError"></f:ajax>
</h:inputText>
<h:message for="eMail" id="emailError" />
<h:commandButton value="Sign up" action="#{user.addUser}" class="waves-effect waves-light btn" type="submit" />
</h:form>
Email.java
import java.util.regex.Pattern;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.FacesValidator;
import javax.faces.validator.Validator;
import javax.faces.validator.ValidatorException;
#FacesValidator("emailValidator")
public class Email implements Validator {
private static final Pattern EMAIL_PATTERN = Pattern.compile("[\\w\\.-]*[a-zA-Z0-9_]#[\\w\\.-]*[a-zA-Z0-9]\\.[a-zA-Z][a-zA-Z\\.]*[a-zA-Z]");
#Override
public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
if( value == null) {
return;
}
String email = (String) value;
boolean matches = EMAIL_PATTERN.matcher(email).matches();
if(!matches) {
FacesMessage msg = new FacesMessage(
FacesMessage.SEVERITY_FATAL,
"Email is invalid",
null);
throw new ValidatorException(msg);
}
}
}
UserBean.java
So, I thought it might make sense to call a function validateEmail in the UserBean and then call the validate function within the Validator Class. But I am really not sure about this. How would I pass the parameters context, component and value?
public void validateEmail(AjaxBehaviorEvent e) {
// Email emailValidator = new Email();
// emailValidator.validate(context, component, value);
}

Answer 1

You could validate your email in your XHTML files.
For that, have a look on this:
Email validation using regular expression in JSF 2 / PrimeFaces
So you only actually need to validate, if Username or Email already exists. You can do that in a validation class for the University.
If you have a validation in your UserManager already, you can use that in the validation class.
regards