xmlv: XML and XSD Validator
Usage
To check an XSD:
java -jar xmlv.jar -c {catalog.xml} -f -a {file.xsd}
To validate an XML instance:
java -jar xmlv.jar -c {catalog.xml} -f -a {file.xsd} -i {file.xml}
Background
Often during projects for which I have to create XML Schemas, I want
to be sure that I'm not making any mistakes. I want to validate the
XSD itself in a manner similar to how any given XML instance file can
be validated against an XSD. Past possibilities have included:
1. Treat the XSD as an XML file to be validated against the XML Schema
schema for XML Schemas:
http://www.w3.org/2001/XMLSchema.xsd
The problem with this approach is that there are limits to what can be
expressed in XML Schema, so this sort of recursive self-check is
necessarily weak.
2. Use IBM's XML Schema Quality Checker. This was my preferred
approach for many years. Then, while automatically generating large
numbers of XSDs for the USPTO, I encountered sets of included XSDs for
which SQC never returned. Unfortunately, SQC is not an open source
project, and support seems to have long been discontinued: Its forum
is inactive back through 2004:
http://www.ibm.com/developerworks/forums/forum.jspa?forumID=707
And no new releases have occured since version 2.1 in 2003:
http://lists.w3.org/Archives/Public/xmlschema-dev/2003Jul/0102.html
After a decade of keeping my XSDs solid via SQC, I needed an
replacement. So, I wrote xmlv, a thin wrapper around Xerces-J, a
battle-hardened XML parser. The Xerces project includes an
XMLGrammarPreparser class that performs extensive checks when loading
an XSD. Xmlv uses XMLGrammarPreparser at its core. It borrows from
the sample Xerces v2.11 sample program, XMLGrammarBuilder.java, by
Neil Graham and includes support for XML Catalogs. Xmlv provides
reliable XSD checking, and it tackled the knarly USPTO modular XSD set
without getting stuck in an infinite loop like SQC did. (It also does
routine XML instance validation too.) It's my new go-to tool for XML
validation and XSD checking.
Kenneth J Hughes (kjh@entel.com)
2013-04-04