[TRINIDAD][API] JIRA 1650 - add support for "empty field validation" and BeanValidation API

[Jing Wu <ji...@oracle.com>]

Hi,

JSF2.0 has support for running validation on empty fields, which 
integrated with BeanValidation. This was implemented and tracked via 
JIRA issue 1650 <https://issues.apache.org/jira/browse/TRINIDAD-1650> a 
while ago.

Now we'll need to backport part of it in earlier releases, more 
specifically, we need to backport the support of running validation on 
empty fields. JavaBean Validation is a new validation model available as 
part of Java EE 6 platform, which is not available in early releases.

To support validation on empty fields, the public context parameter 
org.apache.myfaces.trinidad.UIXEditableValue.VALIDATE_EMPTY_FIELDS 
introduced in the original JIRA issue will be backported. When this 
parameter is set to true, validators will be invoked for validation. 
Default value is false for backward compatibility.

Please let me know if you have any comment.

Thanks,
Jing