This presentation is a brief overview of the JSF custom validators provided by OmniFaces (e.g. cross-field validators). Some OmniFaces validators fixes a suite of gaps of the JSF standard validators, while others are totally new.

1. OmniFaces Validators
Anghel Leonard

2. What we will cover ?
• JSF Validators – short overview
• OmniFaces Validators – short overview
• ValidateBean
• RequiredCheckboxValidator
• ValueChangeValidator
• ValidateUniqueColumn
• JsfLabelMessageInterpolator
• OmniFaces Validator family

3. JSF Validators – short overview (I)
• JSF developers are familiar with JSF built-in validators (which are
tag handlers) and JSF custom validators (implementations of
javax.faces.validator.Validator interface).
• Commonly, JSF validators are attached to inputs (e.g. <h:inputText>)
via validator attribute or <f:validator>/<f:validateXxx> tags.

4. JSF Validators – short overview (II)
• JSF validators are by default processed in the Process Validations
phase. Converters are invoked in this phase (e.g. getAsObject()), but
in Render Response phase also (e.g. getAsString()).
• If the validation fails then JSF marks this via validationFailed flag, at
context level, and via valid flag, at input level.
• Moreover, the JSF lifecycle “jumps” to the Render Response phase,
instead of continue with the Update Model Values phase.

5. OmniFaces Validators – short overview (I)
• Some OmniFaces validators fixes a suite of gaps of the JSF
standard validators, while others are totally new.
• Depending on their goal, OmniFaces validators are implementations
of javax.faces.validator.Validator interface, are tag handlers (extends
TagHandler) or even UIComponent instances.

6. OmniFaces Validators – short overview (II)
• While JSF doesn’t support cross-field validation (not even for
<f:validateBean>), OmniFaces provides several validators that
implements different validation constrains for cross-field validation.
• OmniFaces validators are easy to use and the OmniFaces
Showcase provides complete and dedicated examples.

7. OmniFaces ValidateBean (I)
• The built-in <f:validateBean> allows validation control only on a per-
form or a per-request basis, and only applies to individual properties
of a bean
• The OmniFaces <o:validateBean> allows the developer to control
bean validation on a per-UICommand or UIInput component basis, as
well as validating a bean at the class level

8. OmniFaces ValidateBean (II)
• At class level, validation can be of two types: validate copy and
validate actual bean.
• Validate copy (default) - make a copy of the object to validate at the
end of Process Validations phase, set the values retrieved from the
input components on it, and performs class level validation on the
copy. Does not update the model if validation errors occur.
• Validate actual bean - the validation takes places after the Update
Model Values, so the original bean is first updated with the values
retrieved from the input components, afterwards validated.

9. OmniFaces ValidateBean (III)
• Sample of using <o:validateBean> - screenshots from Showcase
Validating at the class level that number 1 is smaller
than number 2 - default (validate copy)

10. OmniFaces RequiredCheckboxValidator (I)
• If you need to report the un-ticked checkboxes as invalid inputs then
use the OmniFaces RequiredCheckboxValidator validator.
• The RequiredCheckboxValidator solves the problem with required="true"
attribute of UISelectBoolean components (<h:selectBooleanCheckbox>). In
case of UISelectBoolean the validation will pass for both, ticked/un-
ticked checkboxes.

11. OmniFaces RequiredCheckboxValidator (II)
• This validator is used by indicating the validator ID (validatorId
attribute) omnifaces.RequiredCheckboxValidator in <f:validator> of the
boolean selection component.
• The validator will use the message as specified in requiredMessage
attribute, or the default required message as specified in custom
<message-bundle> in faces-config.xml, or it will default to: {0}: a tick is
required.

12. OmniFaces RequiredCheckboxValidator(III)
• Sample of using RequiredCheckboxValidator - screenshots from Showcase
Form with RequiredCheckboxValidator

13. OmniFaces ValueChangeValidator (I)
• At each postback request, the validation process validates the
corresponding submitted values, regardless of whether the submitted
values has changed or not.
• Most likely, we don’t want to re-validate unchanged data.
• In terms of performance, these unnecessarily validations my becomes
too “expensive”. When that happens, is time for ValueChangeValidator.
• The ValueChangeValidator can be used via a transparent template.
Mainly, just replace implements Validator by extends ValueChangeValidator
and rename the method from validate to validateChangedObject.

14. OmniFaces ValueChangeValidator(II)
A JSF common custom validator modified to use ValueChangeValidator
• Sample of using ValueChangeValidator - screenshots from Showcase
A JSF common custom validator

15. OmniFaces ValidateUniqueColumn (I)
• The <o:validateUniqueColumn> validates if the given UIInput component in
an UIData component has an unique value throughout all rows. Those
not visible by pagination are also validated.
• This validator works directly on the data model and may therefore not
work as expected if the data model does not represent all available
rows of the UIData component (e.g. when there's means of lazy
loading).

16. OmniFaces ValidateUniqueColumn (II)
• In an invalidating case, only the first row on which the value is actually
changed will be marked invalid and a faces message will be added on
the client ID of the input component in the particular row.
• The default message is: {0}: Please fill out an unique value for the
entire column. Duplicate found in row {1}

17. OmniFaces ValidateUniqueColumn (III)
• Sample of using ValidateUniqueColumn- screenshots from Showcase
DataTable with ValidateUniqueColumn

18. OmniFaces JsfLabelMessageInterpolator(I)
• In Bean Validation, if a component causes a validation failure, then
the label associated with this component can appear only in the front
or behind the error message. This is possible thanks to
javax.faces.validator.BeanValidator.MESSAGE bundle key.
• OmniFaces comes with a custom message interpolator that allows
developers to place the label associated with the invalid component
anywhere in the error message.

19. OmniFaces JsfLabelMessageInterpolator(II)
• In order to use the JsfLabelMessageInterpolator, the developer must
register it in /META-INF/validation.xml via <message-interpolator> , and
use the special placeholder {jsf.label} in bean validation messages.
• Message example: javax.validation.constraints.Size.message = The size
of {jsf.label} must be between {min} and {max} characters

20. OmniFaces JsfLabelMessageInterpolator(III)
• Sample of using JsfLabelMessageInterpolator - screenshots from Showcase
Demo for JsfLabelMessageInterpolator

21. OmniFaces Validator family
The OmniFaces Validator family represents a collection of cross-field
validators implemented as JSF custom components. Below you can see
the Validator family API.

22. OmniFaces ValidateOne
• The <o:validateOne> validates if ONLY ONE of the given UIInput
components have been filled out.
• The default message is: {0}: Please fill out only one of those fields
Screenshots Showcase

23. OmniFaces ValidateOneOrMore
• The <o:validateOneOrMore> validates if at least ONE of the given UIInput
components has been filled out.
• The default message is: {0}: Please fill out at least one of those
fields
Screenshots Showcase

24. OmniFaces ValidateAllOrNone
• The <o:validateAllOrNone> validates if at least ALL of the given UIInput
components have been filled out or that NONE of the given UIInput
components have been filled out.
• The default message is: {0}: Please fill out all or none of those fields
Screenshots Showcase
You can also show message on all invalid fields, invalidate only the empty fields or
invalidate only the empty fields and show message only on invalid fields

25. OmniFaces ValidateOneOrNone
• The <o:validateOneOrNone> validates if ONLY ONE of the given UIInput
components has been filled out or that NONE of the given UIInput
components have been filled out.
• The default message is: {0}: Please fill out only one or none of those
fields
Screenshots Showcase

26. OmniFaces ValidateAll
• The <o:validateAll> validates if ALL of the given UIInput components
have been filled out. One could of course also just put required="true"
on all of those UIInput components, but this is not always the case
(e.g. having a single message for all invalid UIInput).
• The default message is: {0}: Please fill out all of those fields
Screenshots Showcase

27. OmniFaces ValidateEqual
• The <o:validateEqual> validates if ALL of the given UIInput components
have the same value.
• The default message is: {0}: Please fill out the same value for all of
those fields
Screenshots Showcase

28. OmniFaces ValidateUnique
• The <o:validateUnique> validates if ALL of the given UIInput
components have an unique value.
• The default message is: {0}: Please fill out an unique value for all of
those fields
Screenshots Showcase

29. OmniFaces ValidateOrder (I)
• The <o:validateOrder> validates if the values of the given UIInput
components as specified in the required components attribute are in the
order as specified by the optional type attribute which accepts the
following values:
• lt (default) - from least to greatest, without duplicates.
• lte - from least to greatest, allowing duplicates (equal values next to
each other).
• gt - from greatest to least, without duplicates.
• gte - from greatest to least, allowing duplicates (equal values next to
each other).

30. OmniFaces ValidateOrder (II)
• The to-be-validated values must implement Comparable.
• This validator throws an IllegalArgumentException when one or more of
the values do not implement it.
• Note that when this validator is placed before all of the components,
then it will only compare the raw unconverted submitted string values,
not the converted object values.
• If you need to compare by the converted object values, then you need
to place this validator after all of the components.

31. OmniFaces ValidateOrder (III)
• The <o:validateOrder> validates if the values of the given UIInput
respects a certain order.
• The default message is: {0}: Please fill out the values of all those
fields in order
Screenshots Showcase

32. OmniFaces ValidateMultiple (I)
• The <o:validateMultiple> allows the developer to validate multiple fields
by a custom validator method:
<!-- source code: OmniFaces Showcase -->
<o:validateMultiple id="myId" components="foo bar baz"
validator="#{bean.someMethod}" />
<h:message for="myId" />
<h:inputText id="foo" />
<h:inputText id="bar" />
<h:inputText id="baz" />
Method has the following signature (method name is free to your choice):

33. OmniFaces ValidateMultiple (II)
• The <o:validateMultiple> also allows to validate multiple fields by a
managed bean that implements the MultiFieldValidator interface:
<!-- source code: OmniFaces Showcase -->
<o:validateMultiple id="myId" components="foo bar baz"
validator="#{validateValuesBean}" />
<h:message for="myId" />
<h:inputText id="foo" />
<h:inputText id="bar" />
<h:inputText id="baz" />
Managed bean signature (bean name is free to your choice):

34. References
• Bauke Scholtz - http://balusc.blogspot.com/
• Arjan Tijms - http://arjan-tijms.omnifaces.org/
• JSF ZEEF page - https://jsf.zeef.com/bauke.scholtz
• OmniFaces ZEEF page - https://omnifaces.zeef.com/bauke.scholtz
• OmniFaces Wikipedia - http://en.wikipedia.org/wiki/OmniFaces