public abstract class ValueChangeValidator extends Object implements Validator
By default, JSF validators run on every request, regardless of whether the submitted value has changed or not. In case of validation against the DB on complex objects which are already stored in the model in a broader scope, such as the view scope, this may result in unnecessarily expensive service/DAO calls. In such case, you'd like to perform the expensive service/DAO call only when the submitted value is really changed as compared to the model value.
This validator offers you a template to do it transparently. To use it, just change your validators from:
public class YourValidator implements Validator {
public void validate(FacesContext context, UIComponent component, Object submittedValue) {
// ...
}
}
to
public class YourValidator extends ValueChangeValidator {
public void validateChangedObject(FacesContext context, UIComponent component, Object submittedValue) {
// ...
}
}
So, essentially, just replace implements Validator by extends ValueChangeValidator and
rename the method from validate to validateChangedObject.NOT_IN_RANGE_MESSAGE_ID| Constructor and Description |
|---|
ValueChangeValidator() |
| Modifier and Type | Method and Description |
|---|---|
void |
validate(FacesContext context,
UIComponent component,
Object submittedValue)
If the component is an instance of
EditableValueHolder and its old object value is equal to the
submitted value, then return immediately from the method and don't perform any validation. |
abstract void |
validateChangedObject(FacesContext context,
UIComponent component,
Object submittedValue)
Use this method instead of
validate(FacesContext, UIComponent, Object) if you intend to perform the
validation only when the submitted value is really changed as compared to the model value. |
public void validate(FacesContext context, UIComponent component, Object submittedValue)
EditableValueHolder and its old object value is equal to the
submitted value, then return immediately from the method and don't perform any validation. Otherwise, invoke
validateChangedObject(FacesContext, UIComponent, Object) which may in turn do the necessary possibly
expensive DAO operations.public abstract void validateChangedObject(FacesContext context, UIComponent component, Object submittedValue)
validate(FacesContext, UIComponent, Object) if you intend to perform the
validation only when the submitted value is really changed as compared to the model value.context - The involved faces context.component - The involved UI component.submittedValue - The submitted value.Copyright © 2012–2018 OmniFaces. All rights reserved.