JSF validation error message displayed after manual validation in bean

Question

I am learning JSF and need some help in understanding JSF validation. I am trying to do manual, implicit and explicit validation in same page with the help of "http://courses.coreservlets.com/". I wrote 2 input fields with the validaiton as below.

Customer Name: <h:inputText value="#{bean.customerName}" required="true" />         
       Account No: <h:inputText value ="#{bean.accountNo}" > 
        <f:validateLength minimum="10"></f:validateLength>
       </h:inputText>          
       <h:commandButton value="Submit" action="#{bean.actionValidate}"></h:commandButton>          
       <h:messages globalOnly="true"></h:messages>

public String actionValidate(){     
    FacesMessage fcMessage = new FacesMessage();
    if(getAccountNo().isEmpty() || getAccountNo() == null) {
        fcMessage.setSummary("account no empty");
        fcContext.addMessage(null, fcMessage);
    }       
    if (fcContext.getMessageList().size()>0)
        return null;
    else
        return "ManualValidationResult";
}

My understanding is required attribute of filed 1 and f:validateLength validation will be performed in Process & Validation phase and if the validation fails, the life cycle advances to Render response phase and displays the error message first. once this is passed, the bean validation should be executed - ideally in my example, the validation in the bean will not be executed by any chance. However, I am getting the "Customername - Validation Error: Value is required." if both the fields left blank.

I filled in name field, now I get the "account no empty" message, and later "Validation Error: Length is less than allowable minimum of '5'" if some value is entered in account no field.

Can anyone help me understand the flow please?

BalusC · Accepted Answer · 2013-11-07 17:18:13Z

2

Fact 1: Action methods are invoked during INVOKE_APPLICATION phase.

Fact 2: When standard validation fails during PROCESS_VALIDATIONS phase, then the subsequent UPDATE_MODEL_VALUES and INVOKE_APPLICATION phases are skipped and JSF will directly proceed to execute the RENDER_RESPONSE phase.

Logical consequence: when standard validation fails, action methods are never invoked. This is a Good Thing. Business logic should never be performed with invalid input.

Solution is simple: don't do validation in action methods. I understand that the tutorial is exemplary, but in real world you should avoid such case. Instead of

<h:inputText value ="#{bean.accountNo}">

you should use

<h:inputText value ="#{bean.accountNo}" required="true" requiredMessage="account no empty">

and remove all the validation logic from action method. In fact, your whole action method is useless. You could just use action="ManualValidationResult" instead in the command button. The action is never invoked anyway when validation has failed and thus the navigation is also never performed when validation has failed.

answered Nov 7, 2013 at 17:18

BalusC

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3 Comments

kavitha Over a year ago

Thanks for your time. I agree the action method makes no sense. But I am just trying out all JSF features. I am not clear yet, as you say when I leave the fields blank, the standard validation (here - required validation & f:validateLength minimum="10") should be performed before the action call which means I should get

BalusC Over a year ago

This is also what is happening? Your question at least describes exactly that. The customer name field is not validated in action method at all.

kavitha Over a year ago

sorry,with the code,I expect the output as. 1.leave customer name & acc no blank- I should get error msg "Value is required" for customer name "Length is less than allowable minimum 5" for acc no 2.now fill in both fields, next page dispalys but what I am getting is. 1.leave cust name & acc no blank "Value is required" for cust name is shown but-"Length is less than allowable minimum 5" is not shown 2. fill in customer name & leave acc no blank "account no empty" is shown after action call 3. fill in acc no also "Length is less than allowable minimum 5" for acc no is shown. is this correct?

kavitha · Accepted Answer · 2013-11-09 04:41:44Z

0

f:validatelength works only if some value is associated with the field. If the input field is null, LengthValidator doesn't do any validation. Piece of code from LengthValidator...

// VALIDATE
 public void More ...validate(FacesContext facesContext,
                      UIComponent uiComponent,
                      Object value)
         throws ValidatorException
 {
     if (facesContext == null) throw new NullPointerException("facesContext");
     if (uiComponent == null) throw new NullPointerException("uiComponent");

     if (value == null)
     {
         return;
     }
// length validation code here...
}

answered Nov 9, 2013 at 4:41

kavitha

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