Metadata and Metamodeling

Document and Object Modeling

The WWW Consortium recommends a document model to standardize the ways XML documents are handled. W3C Document Object Model (DOM) [111] defines the object structure of W3C compliant Web pages. Level 2 and Level 3 specifications add event and abstract schema interfaces into the DOM. In detail,

  • XML Schema, and DOM Level 3 (Abstract Schema) define document object structure, 
  • DOM Level 3 (Load, Save and Validation) defines document object persistence and validity,
  • XPath and DOM Level 1 define document object constructors and access mechanisms,
  • and finally DOM Level 2 (Events) helps define event models for distributed applications.

Fox [38] discusses the necessity of defining Web objects and sharing over distributed computing environments, as well as the importance of XML object architecture where he describes the XML Schema as “an elegant and powerful way of expressing an XML data instance’s general object structure” in [41]. Fox points out that not only the properties of objects but also the methods of objects must be considered as data. This approach does not distinguish between properties and methods. Indeed, XML-data binding solutions (i.e., [51, 103]) implement each schema element with a pair of setter/getter methods when programming language object models are generated from a schema. These methods can run more complex tasks, and return the results as element values. As a result, all the XML data, whether it be metadata about real objects or data about a job submission, are equivalent and can be treated as XML objects in general.

Meta Objects

XML objects are actually representatives of real objects in the world of markup languages. They contain data about objects which themselves can also be called electronic objects. We label XML objects that defines real objects XML meta objects, or metaobjects henceforth, and investigate technologies and architectures to build a framework with necessary technologies to create, manage, search, render, and share them over distributed networks and services ubiquitously.