A short entry to explain how to do field validation in Oracle MAF. As an example let's suppose you want a field to have a value before someone clicks to do an operation.
To do that you can set the field's attribute for required and "show required" like this:
<amx:inputText label="label1" id="it1" required="true" showRequired="true"/>
Now if you run your page, leave the field empty and click a button that navigates to another page, you'll notice that there was no indication of an error. This is because you didn't tell the AMX page to actually do a validation.
To add validation you use an amx:validationGroup tag that will surround the fields you want to validate.
For example:
<amx:validationGroup id="vg1">
<amx:inputText label="label1" id="it1" required="true" showRequired="true"/>
</amx:validationGroup>
Then you can add a amx:validateOperation tag to the button that does navigation and tell it to validate the group you defined before (vg1 in our example).
<amx:commandButton id="cb2" text="go" action="gothere">
<amx:validationBehavior id="vb1" group="vg1"/>
</amx:commandButton>
Now when you run the page and try to navigate you'll get your validation error.
