Custom Validators using JSF
The custom validators are user-defined validators that are created to meet application-specific validation. (For Standard Validators check here)
Custom Validators can be created in 2 ways
- Implementing Validator Interface
- Use Bean Method
Example: Lets create a JSF page to check if the person is eligible to vote using custom validators
Steps:
1. Create cvalidator java class and implement validator, write a function for validation
2. JSF Managed Bean
3. Register Custom validator class in faces-config.xml or using Annotations
4. Bind it with the UI component in JSF page
Implementing Validator Interface:
Create a java class and implement validator interface.
cvalidator.java
public class cvalidator implements Validator {
@Override
public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
int bdate=(Integer)value;
if(bdate<=18)
{
FacesMessage message=new FacesMessage();
message.setSummary("You are Underage");
message.setSeverity(FacesMessage.SEVERITY_ERROR);
throw new ValidatorException(message);
}
}
}
JSF Managed Bean – age.java
import javax.inject.Named;
import javax.enterprise.context.Dependent;
import javax.faces.bean.ManagedBean;
/**
*
* @author Vikram
*/
@Named(value = "age")
@Dependent
@ManagedBean
public class age {
int cage;
public int getCage() {
return cage;
}
public void setCage(int cage) {
this.cage = cage;
}
public age() {
}
}
Registering Custom Validator class:
This can be done in 2 ways,
- Register in faces-config.xml
- using Annotations
Faces-config.xml:
<validator> <validator-id>cvalidator</validator-id> <validator-class>cvalidator</validator-class> </validator>
Annotations:
@FacesValidator(value="cvalidator")
index.xhtml
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html"
xmlns:c="http://java.sun.com/jsf/core">
<h:head>
<title>Custom Validator</title>
</h:head>
<h:body>
<h:form>
<h:outputLabel value="Enter your Age"/>
<h:inputText value="#{age.cage}">
<c:validator validatorId="cvalidator"/>
</h:inputText>
<h:commandButton value="Validate" action="index"/>
</h:form>
</h:body>
</html>
Bean Method:
JSF ManagedBean – age.java
import javax.inject.Named;
import javax.enterprise.context.Dependent;
import javax.faces.bean.ManagedBean;
@Named(value = "age")
@Dependent
@ManagedBean
public class age {
int cage;
public int getCage() {
return cage;
}
public void setCage(int cage) {
this.cage = cage;
}
public age() {
}
public void Validate(FacesContext fc,UIComponent c, Object value) throws ValidatorException
{
int bdate=(Integer)value;
if(bdate<=18)
{
FacesMessage message=new FacesMessage();
message.setSummary("You are Underage");
message.setSeverity(FacesMessage.SEVERITY_ERROR);
throw new ValidatorException(message);
}
}
}
index.xhtml
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html"
xmlns:c="http://java.sun.com/jsf/core">
<h:head>
<title>Custom Validator</title>
</h:head>
<h:body>
<h:form>
<h:outputLabel value="Enter your Age"/>
<h:inputText value="#{age.cage}" validator=#{age.validate}">
</h:inputText>
<h:commandButton value="Validate" action="index"/>
</h:form>
</h:body>
</html>
Output:
