resourceRef modifier Attribute

The "modifier" attribute of the <resourceRef> element specifies the override requirements for the resource.

If ABSTRACT, the resourceRef <resource> element is omitted and must be specified by non-abstract derived components. ResourceRefs may only be declared abstract if the component is also declared abstract. Non-abstract resourceRefs must declare a <resource> element.

If FINAL, the resourceRef may not be overridden by derived components.

If unspecified, then derived components can choose whether or not to override the resourceRef.