The JAXP XPath API

Saxon implements the JAXP 1.3 API for executing XPath expressions as defined in package java.xml.xpath, which is a standard part of the Java class library since JDK 1.5. Three sample applications using this API are available: they are called XPathExample.java, XPathExampleSA.java, and ApplyXPathJAXP.java, and can be found in the samples/java directory after downloading the saxon-resources archive.

To run the XPathExample.java application, see the instructions in Shakespeare XPath Sample Application.

The XPathExampleSA.java application demonstrates use of schema-aware XPath. It is designed to be used with the files books.xml and books.xsd in the directory samples/data.

The ApplyXPathJAXP.java application is an enhanced version of the class of the same name issued as a sample application in the JAXP 1.3 distribution. It has been enhanced to show the use of more advanced features, such as the ability to bind namespaces, variables, and functions, and also to demonstrate use of the XPath API with different object models.

The XPath API in Saxon predates the introduction of the JAXP 1.3 XPath API, so it contains some facilities that are obsolescent. However, there are also differences caused by the fact that Saxon supports XPath 2.0, with its richer data model, whereas JAXP 1.3 operates only on XPath 1.0.

The following sections describe use of the XPath API in more detail.

• Selecting the XPath implementation: Describes how to ensure that Saxon is selected as the XPath API implemenation

• Setting the context item: Describes how to supply a context item

• Return types: Describes the mapping of XPath return types to Java classes

• Additional Saxon methods: Describes features of the Saxon implementation additional to the JAXP specification

• Calling JAXP XPath extension functions: Describes how to call out from XPath expressions to Java code

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