The Universal Business Library (UBL) has embraced many of the object-oriented aspects of W3C XML Schema (XSD) in its approaches to versioning, customization of schemas, and overall library management. The type-aware features of XSD are a critical element in enabling the broadest possible degree of interoperability across versions and between customized schemas sharing a common base. These features of XSD are not widely appreciated, despite being clearly intended to offer users a great deal of power within applications, for a number of reasons.

One of the main reasons is that the kinds of type-aware processors that this approach relies on for maximum benefit are only now starting to appear. XPath version 2.0 will embrace XSD's type-awareness, allowing matching not only on element names but on elements sharing a common type anywhere in their tree. By making XSLT type-aware, a major shift will happen, enabling the object-oriented direction embraced by the UBL design.

Other applications will also increasingly rely on a type-aware approach, using information found in the post schema validation infoset ("PSVI") to exhibit object-oriented behaviors consistent with the XSD specification.

Building up on a series of talks that the authors have presented over the last couple of years both at USA XML200X and XMLEurope200X, this paper reviews UBL use cases for type-awareness, including versioning and namespace packaging, customization and the automation of "business context", as well as issues around interoperability. For each case, the behaviors needed in applications will be demonstrated, with an emphasis on schema and instance examples, the PSVI, and requisite application behaviors. Those standards that are expected to be important for the creation of type-aware applications will be highlighted (including XPath 2.0, XSLT, and XSD). The availability of tools and their functionality in this area will be covered. Further, the implications of this strategy for application architectures and business automation strategies will be explored.

The specific benefits and liabilities of this approach will be explored and discussed. The UBL design justifications for the choice of an object-oriented approach to these difficult issues will be presented from the perspective of those implementing e-business systems.

With the advent of type-aware specification and their utilization by applications like UBL, we can truly say "now we're cooking" -- and this paper attempts to show implementors exactly how UBL (and, by extension, other type-aware XML applications) can serve as a powerful basis for creating interoperable e-business applications.