NewsML Toolkit 1.1beta
22:13, 26 Nov 2001 UTC | Eric van der Vlist

David Megginson has announced  NewsML Toolkit 1.1beta, "an extensive rewrite of version 1.0" still "kindly sponsored" by Reuters PLC and published under an open source (LGPL) license.

Beyond the features specific to the NewsML application, this toolkit could probably be used as an example of best practices for writing Java APIs for XML applications. The toolkit is published with a good deal of documentation, including an "architectural overview".

The package has been decoupled from the parser API through a factory. Although this beta release only includes a factory interfaced with the DOM, Megginson explains how and why other factories might be developed:

  • A backend built using the Simple API for XML (SAX) interface would be able to read a NewsML package in a quick, single pass, with minimum memory overhead.
  • A backend built on top of a database could execute database queries directly to build the different parts of a NewsML document.
  • A validating backend could apply business rules to every part of the NewsML package as it is queried.
  • A masquerading backend could make data in another news-industry format appear as NewsML to an application.

Another area of generic interest is the conformance testing toolkit, which lets people register their own conformance tests written in Java and performed on the nodes of a node set returned by an XPath expression. This principle appears to be similar to Schematron assertions except that the tests are written in Java while Schematron assertions are written using XPath/XSLT. This framework comes with general tests validating the NewsML rules and can be used to add other specific tests:

Starting with version 1.1beta, the NewsML Toolkit includes support for testing a NewsML document's conformance to the functional specification. Low-level DTD-based structural validation is available through the underlying XML parser; higher-level, conformance testing is now handled by the org.newsml.toolkit.conformance package. The conformance framework is fully open and configurable, so users can easily add conformance tests for local business logic.

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