Different use of validator

[Himai Minh]

Hi , everyone
Let me give you a hint about validator. We have to memorize the 4 different usage of validator attribute.
1. CDI validator.
For example

@Named ("xxxValidator")
public class XXXValidator implements Validator{

@Override
public void validate(FacesContext context, UIComponent compoent, Object object) throws ValidatorException {....}
}

  <h:inputText ... >
      <f:validator binding="#{xxxValidator}"/>

 </h:inputText>

2. Use @FacesValidator

@FacesValidator ("xxxValidator")
public class XXXValidator implements Validator{

@Overrides
public void validate (FacesContext context, UIComponent component, Object value) throws ValdiatorException{

   ....
}
}

   <h:inputText ...>

         <f:validator validatorId="xxxValidator"/>
   </h:inputText>

3. Use validator defined in faces-config.xml
For example,

package com.practice;
 public class XXXValidator implements Validator{

    @overrides
     public void validate (FaceContext context, UIComponent component, Object value) throws ValidatorException{
         ...

     }

  }
 In faces-config.xml
<validator>
           <validator-id>customValidator</validator-id>
           <validator-class>com.practice.XXXValidator</validator-class>    //make sure it is a fully qualified name
 </validator>

 <h:inputText ...>
           <f:validator validatorId="customValidator"/>
 </h:inputText>

4. Use bean validator

   @Named ("myBean")
   public class examBean {
 
    public void validateExamName (FacesContext context, UIComponent component, Object value) throws ValidateException {...}

   }

<h:inputText ... validator="#{myBean.validateExamName}">

2 and 3 are the same except that one uses annotation while another one uses faces-config.xml
1 , 2, 3 uses <f:validator> facelet. When you are using CDI validator, you use binding = "validator name" When you are using validator, you use validatorId="validator id".
4 is different as the bean itself has its own validator method taking FacesContext, UIComponent and Object as arguments.

In the exam, you may be asked to change from case 1 to case 4, or something like that.