XML-based rules

XML descriptions of XML processing The easiest means of configuring filters that I've found is creating XML documents which describe the configuration. You can also configure the filter manually through Java, but XML documents are much more portable and easy to deal with.
Matching Names The Regular Fragmentations filter is namespace-aware. In the configuration file, I avoided some practices I really detest, like the use of QNames in attribute values or element content, so it's a slightly different approach.
Regular expressions at the core W3C XML Schema regular expressions are supported through the Regular Expressions utility package of the Apache Xerces processor.
Temporary syntax, plug-in model I don't claim that my rules file syntax is final or perfect, but it does quite well for now. (I fear premature optimization more than any current imperfection.) Also, developers can change the regex engine and use additional regex syntax (at risk, of course!).