CODEWITHSUNDEEP
javawicketvalidation
alexD
alexD

Reputation: 2364

Wicket validator doesn't raise error on null field value

How do I get my validator to raise an error on a null value? I can see through my logs that when I try to submit a null field it's calling the validator, but it never raises onError so I cannot handle this. I want to display an error message in a feedback panel when someone tries to submit an empty field instead of having to do a check in onSubmit of my form.

@Override
protected void onValidate(IValidatable<String> validatable) {

    String value = validatable.getValue();

    if (value == null) {
        ValidationError error = new ValidationError();
        error.addMessageKey("messageKey");
        validatable.error(error);
    }

}

@Override
public void validateOnNullValue() {
     return true;
}

Edit

If the above is not easily possible, is there a way that I can easily register an error message with a feedback panel when component.setRequired is true and the form is submitted with an empty field? I just don't want there to be no feedback to the user when they try to submit the form with an empty field, but I also don't want to have logic for this in the onSubmit handler.

edit 2 SOme more context

Here are two of the fields I'm trying to validate:

final TextField<String> currentLpnField = new TextField<String>("currentLpn", Model.of(""));
currentLpnField.setOutputMarkupId(true);
currentLpnField.setRequired(true);
currentLpnField.add(new BarcodeLPNValidator());

final TextField<String> upcField = new TextField<String>( "upc", new Model<String>() ); 
upcField.setOutputMarkupId(true);
upcField.setRequired(true);
upcField.add(new BarcodeUPCValidator());

Here is what's in my properties file:

upc.null=UPC cannot be null
upc.Required=UPC is required

currentLpn.null=LPN cannot be null
currentLpn.Required=LPN is required

I get the *.Required message only after i've entered info in the field, validated it, then delete it and try validating again. If I just load the form and submit it without ever entering any data, I get nothing.

Upvotes: 1

Views: 3051

Answers (2)

Jon
Jon

Reputation: 55

If you just want to validate a field if it is not empty then set the field required:

component.setRequired(true);

Then add a label for you error message

component.setLabel(Model.of("Username"));

Then add a a FeedbackPanel 

FeedbackPanel feedback = new FeedbackPanel("feedback");
feedback.setOutputMarkupId(true);
form.add(feedback);

To finish, you have to @Override the onError method in your AjaxSubmitLink :

add(new AjaxSubmitLink("save", form) {
    private static final long serialVersionUID = 1L;
    @Override
    protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
        super.onSubmit(target, form);

    }

    @Override
    protected void onError(AjaxRequestTarget target, Form<?> form) {
        super.onError(target, form);
        target.add(feedback);
    }
});

Then if your field will be empty the error message will be:

The field 'Username' cannot be empty.

Upvotes: 0

Robert Niestroj
Robert Niestroj

Reputation: 16151

If you just want to validate a field if it is not empty then set the field required:

component.setRequired(Boolean.TRUE);

Then if you want to provide feedback to the user you have to use a FeedbackPanel. Configure the feedbackPanel to be visible when there are any messages:

private FeedbackPanel feedbackPanel;
feedbackPanel  = new FeedbackPanel("feedbackPanel") {
    @Override
    protected void onConfigure() {
        super.onConfigure(); 
        setVisible(anyMessage());
    }
};
feedbackPanel.setOutputMarkupPlaceholderTag(true);

Then if you submit your form using AJAX you have to add the feedbackPanel to the AjaxRequestTarget to that it will get re-rendere and if there are any (error)messages the feedbackPanel will display the messages:

AjaxButton btn = new AjaxButton("button") {
    @Override
    protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
        super.onSubmit(target, form); 
        target.add(feedbackPanel);
    }
};

Additionally to get a good error message set a label for your component:

component.setLabel(Model.of("Username"));

Then if your field will be empty the error message will be:

The field 'Username' cannot be empty.

Upvotes: 3

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