JAXP factory interfaces

Saxon implements a number of JAXP interfaces, notably the APIs for transformation, XPath processing, and validation.

XSLT

For transformation, the root object of the API is the JAXP TransformerFactory. Saxon provides several implementations of this interface:

For any Saxon edition: net.sf.saxon.TransformerFactoryImpl. This creates the "highest possible" configuration based on what software is in use (without taking into account what license file is deployed). An application creating an instance of this class can therefore use Saxon-PE or Saxon-EE facilities if they are available.
For Saxon-HE: net.sf.saxon.BasicTransformerFactory. This strictly disables all Saxon-PE and Saxon-EE features.
For Saxon-PE: com.saxonica.config.ProfessionalTransformerFactory
For Saxon-EE: com.saxonica.config.EnterpriseTransformerFactory
For streaming with Saxon-EE: com.saxonica.config.StreamingTransformerFactory. This TransformerFactory does not fully comply with the JAXP specifications, because (in the interests of enabling streaming) it does not set the global context item to the root node of the source document; if any global variables in the stylesheet refer to the context item, this will cause a streaming failure.

The JAXP static method TransformerFactory.newInstance() searches the classpath for a JAR file containing a manifest that identifies it as a JAXP transformation engine. If it finds Saxon-HE on the classpath, it will instantiate net.sf.saxon.TransformerFactoryImpl; if it finds Saxon-PE, then ProfessionalTransformerFactory; if Saxon-EE, then EnterpriseTransformerFactory.

The JAXP classpath search is time-consuming, and creates the danger that the application will fail if the classpath is configured incorrectly. Saxonica recommends instantiating the desired TransformerFactory directly, using its own constructor, or by naming the class as the first argument of the TransformerFactory.newInstance() method. Better still, use the s9api interface.

The TransformerFactory interface provides methods getAttribute(name) and setAttribute(name, value) which correspond directly to the methods getConfigurationProperty(name) and setConfigurationProperty(name, value) on the underlying Configuration object. By casting from the JAXP interface to the Saxon implementation class it is also possible to call the getConfiguration method which exposes the Configuration object directly.

The Saxon-PE and Saxon-EE implementations of the TransformerFactory also allow the configuration property CONFIGURATION_FILE to be set. The value is a filename containing the name of a configuration file, which must have the format described in Configuration file. This causes any previously-initialized configuration to be discarded, and replaced with a new Configuration object built from the settings in the specified configuration file.

XPath

Saxon implements the JAXP XPath interface javax.xml.xpath.XPathFactory; the implementation class is net.sf.saxon.xpath.XPathFactoryImpl.

However, the Saxon JAR files do not contain the manifest information that causes Saxon to be picked up as an XPath implementation by the factory method XPathFactory.newInstance(); it must be instantiated directly. This is because an application calling this method is probably expecting to find an XPath 1.0 engine, and is very likely to fail in some way if an XPath 3.1 engine is returned.

The JAXP XPathFactory interface is designed very much around (a) the XPath 1.0 type system, and (b) the DOM as the expected tree model. In addition, it only works with Saxon if the Configuration that underpins the XPathFactory is the same as the Configuration used to build the source document. Use of this interface with Saxon is therefore not very satisfactory, and the s9api interface is strongly preferred.

The JAXP XPathFactory interface has a general-purpose configuration mechanism in the form of the two methods setFeature() and getFeature(). These can be used to set/get all boolean-valued configuration options in the underlying Saxon Configuration, as well as the options defined in the JAXP interface itself. To set configuration options that are not boolean-valued, it is necessary to navigate to the underlying Configuration object and use its native interfaces. Saxon's implementation class for the XPathFactory is net.sf.saxon.xpath.XPathFactoryImpl, regardless which Saxon edition is in use.

XSD (schema processing)

Saxon-EE also implements the JAXP SchemaFactory in class com.saxonica.ee.jaxp.SchemaFactoryImpl. The interface offers methods getProperty(name) and setProperty(name, value) which map to the underlying methods in the Saxon Configuration; again, it is also possible to cast to the Saxon implementation class and call configuration-setting methods directly.