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<h1>The NodeInfo interface</h1>
<p>The <a class="bodylink" href="../javadoc/net/sf/saxon/om/NodeInfo.html"><code>NodeInfo</code></a> object represents a node of an XML document.
It has a subclass <a class="bodylink" href="../javadoc/net/sf/saxon/om/DocumentInfo.html"><code>DocumentInfo</code></a> to
represent the root node, but all other nodes are represented by <code>NodeInfo</code> itself. These follow the
XPath data model closely.</p>
<p><i>In earlier releases, <a class="bodylink" href="../javadoc/net/sf/saxon/om/NodeInfo.html"><code>NodeInfo</code></a>
extended the DOM interface <code>Node</code>. This is no longer the case;
it was changed to make it easier to integrate Saxon with other XML tree representations such as JDOM.
Instead, a new class <a class="bodylink" href="../javadoc/net/sf/saxon/dom/NodeOverNodeInfo.html"><code>NodeOverNodeInfo</code></a>
was introduced, which presents a (read-only) DOM view of a Saxon node.</i></p>
<p>The <a class="bodylink" href="../javadoc/net/sf/saxon/om/NodeInfo.html"><code>NodeInfo</code></a> object provides the application with
information about the node. The most commonly used methods include:</p>
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<p>getNodeKind()</p>
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<p>gets a short identifying the node type (for example, element or attribute). The values are
consistent with those used in the DOM, and are referenced by constants in the class
<a class="bodylink" href="../javadoc/net/sf/saxon/type/Type.html"><code>net.sf.saxon.type.Type</code></a>
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<p>getDisplayName(), getLocalPart(), getPrefix(), getURI()</p>
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<p>These methods get the name of the element, or its various parts. The <code>getDisplayName()</code>
method returns the QName as used in the original source XML.</p>
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<p>getAttributeValue()</p>
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<p>get the value of a specified attribute, as a String.</p>
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<p>getStringValue()</p>
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<p>get the string value of a node, as defined in the XPath data model</p>
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<p>getTypedValue()</p>
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<p>get the typed value of a node, as defined in the XPath 2.0 data model. This is in general a sequence
of atomic values, so the result is a <a class="bodylink" href="../javadoc/net/sf/saxon/om/SequenceIterator.html"><code>SequenceIterator</code></a>.</p>
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<p>getParent()</p>
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<p>get the <a class="bodylink" href="../javadoc/net/sf/saxon/om/NodeInfo.html"><code>NodeInfo</code></a>
representing the parent element, (which will be a
<a class="bodylink" href="../javadoc/net/sf/saxon/om/DocumentInfo.html"><code>DocumentInfo</code></a> object
if this is the outermost element).</p>
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<p>iterateAxis()</p>
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<p>returns an <a class="bodylink" href="../javadoc/net/sf/saxon/om/SequenceIterator.html"><code>SequenceIterator</code></a>
object that can be used to iterate over the nodes on any of the
XPath axes. The first argument is an integer identifying the axis; the second is a
<a class="bodylink" href="../javadoc/net/sf/saxon/pattern/NodeTest.html"><code>NodeTest</code></a> (a
simple form of pattern) which can be used to filter the nodes on the axis. Supply <code>null</code>
if you want all the nodes on the axis. (For most applications, it is probably simpler to navigate
from a node by compiling an XPath expression, and executing it with the correct starting node as
the context node).</p>
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<p>For other methods, see the JavaDoc documentation.</p>
<p>It is possible (though not easy) to provide your own implementation of the <code>NodeInfo</code> interface,
perhaps allowing Saxon queries to run directly against some non-XML data source. There are helper methods in the
<a class="bodylink" href="../javadoc/net/sf/saxon/om/Navigator.html"><code>net.sf.saxon.om.Navigator</code></a> class that reduce the
amount of code you need to write to achieve this.
See the implementations that map <a class="bodylink" href="../javadoc/net/sf/saxon/om/NodeInfo.html"><code>NodeInfo</code></a> to
DOM, DOM4J, JDOM or XOM to see how it is done.</p>
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