A vendor-independent Java interface for RELAX NG datatype libraries has been developed by James Clark and KAWAGUCHI Kohsuke. RELAX NG datatype libraries should be interchangeable between RELAX NG validators that support this interface. The interface is hosted at SourceForge in the relaxng project and documentation.
In particular, the Jing validator now supports this interface.
The interface allows validators to find datatype libraries dynamically at run-time. In order for a validator to be able to find a datatype library:
META-INF/services/org.relaxng.datatype.DatatypeLibraryFactory,
which must contain the name of the class that implements the interface
org.relaxng.datatype.DatatypeLibraryFactoryThis will only work with JDK 1.2 or greater. It will not work with JDK 1.1.
This package contains a very simple example of a datatype library.
The datatype library is implemented by the class
com.thaiopensource.datatype.sample.BalancedString. The
bulk of the implementation is inherited from the abstract class
com.thaiopensource.datatype.sample.SimpleDatatypeLibrary,
which provides default implementations for the methods in the
interfaces which a datatype library must implement. A class that
derives from SimpleDatatypeLibrary has only to implement
a boolean isValid(String literal) method. The datatype
library has the URI
http://www.thaiopensource.com/relaxng/datatypes/sample,
and contains exactly one datatype, which is called
balancedString. This datatype allows any string in which
parentheses are properly balanced (nested). To use this sample
datatype library, simply include datatype-sample.jar in
your CLASSPATH. You will then be able to validate against schemas
using this additional datatype. The file datatype-sample.rng is a simple RELAX
NG schema using this datatype; valid.xml is an
instance that is valid with respect to this schema; invalid.xml is an instance that is not valid
with respect to this schema.