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Package overview for net.sf.saxon.pull
This package provides classes that interface Saxon to an XML parser that supplies data in the form
of a stream of events. It provides an interface, PullProvider, that is an abstraction
over the pull parser interfaces provided on Java and .NET, and that can in principle be implemented
by other data sources to deliver input documents as if they came from a parser.
This package is almost obsolete. Pull-mode processing of queries, when required at all, is generally
done using the classes in the {@link net.sf.saxon.evpull} package, which deliver a stream of events
as objects, rather than as simple integers (analogous to the two styles of pull processing interface
in StAX).
The API, defined in class PullProvider, is loosely modelled on the StAX XMLReader
API. It is not identical, because it is designed as an intimate and efficient interface that integrates with
Saxon concepts such as the SequenceIterator and the NamePool. A class
StaxBridge is available that provides the PullProvider interface on top of a
StAX pull parser. In the .NET build, a similar class DotNetPullProvider interfaces Saxon to the
Microsoft XmlTextReader.
A source of data delivered by a PullProvider may be presented either as a PullSource
or as a StaxSource. Both these are accepted by any Saxon interface that allows a JAXP
Source object to be supplied.
Additional implementations of PullProvider are available in Saxon-PE and
Saxon-EE, specifically, implementations that deliver data by walking a Saxon tree structure
(represented by class NodeInfo), and implementations that allow queries to be evaluated
in pull mode, with lazy construction of temporary document and element nodes.
Some examples of application code using the pull interface with Saxon are provided in the
PullExamples.java file in the samples directory.
Michael H. Kay
Saxonica Limited
10 June 2009