JAXP Source Types
This section is relevant to the Java platform only.
When a user application invokes Saxon via the Java API, then a source document is supplied as an
instance of the JAXP
Source class. This is true whether invoking an XSLT transformation,
an XQuery query, or a free-standing XPath expression. The
is essentially a marker interface. The
that is supplied must be a kind of
Source that Saxon recognizes.
Saxon recognizes the three kinds of
Source defined in JAXP: a
SAXSource, and a
Saxon also accepts input from an
javax.xml.stream.XMLStreamReader), that is
a StAX pull parser as defined in JSR 173. This is achieved by creating an instance of
XMLStreamReader using the
setXMLStreamReader() method, and wrapping the
StaxBridge object in an instance of
net.sf.saxon.pull.PullSource, which implements the JAXP
Source interface and can be used in any Saxon method that expects a
Source. Saxon has been validated
with two StAX parsers: the Zephyr parser from Sun (which is supplied as standard with JDK 1.6), and the open-source Woodstox parser
from Tatu Saloranta. In my experience, Woodstox is the more reliable of the two. However, there is no immediate benefit in using
a pull parser to supply Saxon input rather than a push parser; the main use case for using an
XMLStreamReader is when
the data is supplied from some source other than parsing of lexical XML.
Nodes in Saxon's implementation of the XPath data model are represented by the interface
NodeInfo is itself a
Source, which means
that any method in the API that requires a source object will accept any implementation of
NodeInfo. As discussed in the next section, implementations of
are available to wrap DOM, DOM4J, JDOM, or XOM nodes, and in all cases these wrapper objects can be used
Source is required.
Saxon also provides a class
net.sf.saxon.lib.AugmentedSource which implements the
interface. This class encapsulates one of the standard
Source objects, and allows additional processing
options to be specified. These options include whitespace handling, schema and DTD validation, XInclude processing,
error handling, choice of XML parser, and choice of Saxon tree model.
Saxon allows additional
Source types to be supported by registering a
Configuration object. The task of a
SourceResolver is to convert a
Source that Saxon does not recognize into a
Source that it does recognize.
For example, this may be done by building the document tree in memory and returning the
object representing the root of the tree.