2.4. Presentation layer validation
When working with JSF and JBoss Seam , one can triggers the validation process at the presentation layer using Seam's JSF tags
<s:validate> and <s:validateAll/>, letting the constraints be expressed on the model, and the violations presented in the view
<h:form>
<div>
<h:messages/>
</div>
<s:validateAll>
<div>
Country:
<h:inputText value="#{location.country}" required="true"/>
</div>
<div>
Zip code:
<h:inputText value="#{location.zip}" required="true"/>
</div>
<div>
<h:commandButton/>
</div>
</s:validateAll>
</h:form>
Going even further, and adding Ajax4JSF to the loop will bring client side validation with just a couple of additional JSF tags, again without validation definition duplication.
Check the JBoss Seam documentation for more information.
