Upgrade XSLT engine

[ucaiug-admin]

Given that in release 1.10.0 we will be exposing the internal XSLT transform builders feature to now allow for imports of custom XSLT builders we would like to upgrade the XSLT engine to support XSLT 3.0. Currently, only version 1.0 is supported.

[ucaiug-admin]

After investigating possible options, it is suggested we implement this enhancement using Saxon-HE 10.8.

[ucaiug-admin]

The following software must be installed separately, it is not included with the Saxon download.

To run Saxon you need at least a Java VM, and preferably a Java development environment. Saxon 10 requires at least Java SE 8 (also known as JDK 1.8). It should also run under later Java versions, but this may not be fully tested.

Saxon has options to work with source trees constructed using DOM, JDOM2, XOM, DOM4J, or AXIOM:

To use Saxon with DOM, you do not need any extra code on your classpath. The DOM implementation must support DOM Level-3 interfaces, and the DOM must be built with namespace processing enabled. Saxon is tested with both the DOM implementation provided by the Apache Xerces parser, and the DOM that is packaged with the Oracle JDK. It should work with other DOM implementations, but this can never be 100% guaranteed without testing. Many DOM implementations, especially non-productized implementations, deviate in minor but significant ways from the specifications.

For the other object models, JDOM2, XOM, DOM4J, and AXIOM, the supporting Saxon adapter code is integrated into the JAR files for Saxon-PE and Saxon-EE, but is available only as source code for Saxon-HE. To exploit this code with the open source Home Edition, you will need to compile the source code from the relevant subpackage of net.sf.saxon.option, and register it using the method registerExternalObjectModel on the Configuration object, or via the configuration file. (With Saxon-PE and Saxon-EE, the supported object models are registered automatically if the underlying code is found on the classpath.)

Note that support for JDOM version 1 is dropped in Saxon 10.

By default Saxon uses an XML parser that supports the SAX2 interface. Saxon has been tested successfully in the past with a wide variety of such parsers including Ælfred, Xerces, Lark, SUN Project X, Crimson, Piccolo, Oracle XML, xerces, xml4j, and xp. In the past Saxonica recommended using the Apache version of Xerces in preference to the built-in parser delivered with the JDK, but since JDK 8 the built-in parser appears to be equally reliable. The parser must be SAX2-compliant. All the relevant JAR files must be installed on your Java CLASSPATH.

Saxon will also work with a StAX parser. Generally speaking, StAX parsers are less mature and less interoperable than SAX parsers, and any performance advantage is likely to be very minor. However, the support for StAX provides the ability to supply input via a customized pull pipeline. Saxon is tested with Woodstox 3.0.0. Saxon's schema validation is available only with a SAX2 parser.

Below is an overview of the JAR files included in the Saxon 10.8 product. Highlighted are those that should be deployed as part of the upgrade.

JAR file	Size (approx)	Contents	Included in Editions
saxon-he-10.#.jar	5.4Mb	Saxon Home Edition. Contains all the software in Saxon-HE, except as noted below.	HE
saxon-pe-10.#.jar	6Mb	Saxon Professional Edition. Contains all the software in Saxon-PE, except as noted below.	PE
saxon-ee-10.#.jar	8.3Mb	Saxon Enterprise Edition. Contains all the software in Saxon-EE, except as noted below.	EE
icu4j-59_1.jar	11.9Mb	A copy of the open source ICU-J localization library, used to support sorting and date/number formatting in a wide variety of languages. If this JAR file is not present on the classpath, this will restrict the collations and localization options available to those that are found in the Java runtime. It should be possible to replace this JAR with a later version downloaded from the ICU project. (Previous Saxon releases used a tailored version of this JAR file. With experience, we found that this added complexity and delivered no tangible benefits.)	PE, EE
saxon-xqj-10.#.jar	100Kb	Support for the XQJ (XQuery for Java) API. Provided as a separate JAR file in Saxon-HE so that it can be excluded from distributions that require pure OSI-approved open source licensing. The code is included as an integral part of Saxon-PE and Saxon-EE, so no separate JAR file is required in those cases.	HE
saxon-sql-10.#.jar	61Kb	Supports XSLT and XPath extensions for accessing and updating a relational database from within a stylesheet or query. Provided with Saxon-PE and Saxon-EE. The source code is open source so that it can be modified, but it requires support for element extensibility, which requires Saxon-PE or higher.	PE, EE
saxon-he-test-10.#.jar	127Kb	Test drivers for running the W3C test suites for XSLT and XQuery against Saxon-HE. The test drivers are published as open source code in the saxon-resources download. The test suites themselves are on GitHub: repositories w3c/xslt30-test and w3c/qt3tests.	HE
saxon-pe-test-10.#.jar	176Kb	Test drivers for running the W3C test suites for XSLT and XQuery against Saxon-PE. The test suites themselves are on GitHub: repositories w3c/xslt30-test and w3c/qt3tests.	PE
saxon-ee-test-10.#.jar	215Kb	Test drivers for running the W3C test suites for XSLT, XQuery, and XSD against Saxon-EE. The test suites themselves are on GitHub: repositories w3c/xslt30-test, w3c/qt3tests, w3c/xsdtests.	EE
jline-2.14.6.jar	205Kb	JLine 2: an open source library supporting interactive command-line applications, including content completion and command history. This is used by the Gizmo utility, and must be on the classpath when Gizmo is run (it is not needed otherwise).	HE, PE, EE