[CAMEL-9591] Support Saxon integrated extension functions

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.17.0
• Component/s: camel-xslt
• Estimated Complexity: Unknown
• Assignee: Luca Burgazzoli
• Reporter: Luca Burgazzoli
• Created: 11/Feb/16 15:17
• Updated: 12/Feb/16 12:57
• Resolved: 12/Feb/16 11:05

Description

Since Saxon 9.2, writing extension functions has been supplemented by a new mechanism, referred to as integrated extension functions.

To use such an extension function, user writes a custom class which extends net.sf.saxon.lib.ExtensionFunctionDefinition an registers it in the Saxon transformer factory. It works fine. Only problem is that there's no convenient support in Camel to pass such an extension function reference to camel-xslt.

Current way:

    // Define my extension functions (note: Saxon requires a class for each function)
    List<ExtensionFunctionDefinition> extensionFunctions = new ArrayList<ExtensionFunctionDefinition>();
    extensionFunctions.add(new MyExtensionFunction1());
    extensionFunctions.add(new MyExtensionFunction2());
    
    // Register extension functions
    TransformerFactoryImpl extendedSaxonTransformerFactory = new TransformerFactoryImpl();
    Configuration configuration = extendedSaxonTransformerFactory.getConfiguration();
    for ( ExtensionFunctionDefinition func : extensionFunctions ) {
        configuration.registerExtensionFunction(func);
    }

    // Enable secure processing (note: secure processing allows use of Saxon integrated extension functions as opposed to reflective extension functions)  
    extendedSaxonTransformerFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);

    // Register transformer factory on Camel
    SimpleRegistry registry = new SimpleRegistry();
    registry.put("extendedSaxonTransformerFactory", extendedSaxonTransformerFactory);
    CamelContext context = new DefaultCamelContext(registry);

    // Define Route
    context.addRoutes(new RouteBuilder() {
        @Override
        public void configure() throws Exception {
            from("direct:start")
                .to("xslt:transformation/myStyleSheet.xslt?transformerFactory=#extendedSaxonTransformerFactory");
        }
    });

Proposed way:

    // Define my extension functions (note: Saxon requires a class for each function)
    List<ExtensionFunctionDefinition> extensionFunctions = new ArrayList<ExtensionFunctionDefinition>();
    extensionFunctions.add(new MyExtensionFunction1());
    extensionFunctions.add(new MyExtensionFunction2());

    // Register extension functions with Camel
    SimpleRegistry registry = new SimpleRegistry();
    registry.put("extensionFunctions", extensionFunctions);
    CamelContext context = new DefaultCamelContext(registry);

    // Define Route
    context.addRoutes(new RouteBuilder() {
        @Override
        public void configure() throws Exception {
            from("direct:start")
                .to("xslt:transformation/myStyleSheet.xslt?saxon=true&saxonExtensionFunctions=#extensionFunctions&secureProcessing=true");
        }
    });