net.sf.saxon.s9api

Class XdmNode

java.lang.Object

net.sf.saxon.s9api.XdmValue

net.sf.saxon.s9api.XdmItem

net.sf.saxon.s9api.XdmNode

All Implemented Interfaces:

Iterable<XdmItem>

public class XdmNode
extends XdmItem

This class represents a node in the XDM data model. A Node is an XdmItem, and is therefore an XdmValue in its own right, and may also participate as one item within a sequence value.

An XdmNode is implemented as a wrapper around an object of type NodeInfo. Because this is a key interface within Saxon, it is exposed via this API.

The XdmNode interface exposes basic properties of the node, such as its name, its string value, and its typed value. Navigation to other nodes is supported through a single method, axisIterator(net.sf.saxon.s9api.Axis), which allows other nodes to be retrieved by following any of the XPath axes.

Note that node identity cannot be inferred from object identity. The same node may be represented by different XdmNode instances at different times, or even at the same time. The equals() method on this class can be used to test for node identity.

Since:

9.0

Constructor Summary

Constructors

Constructor and Description
XdmNode(NodeInfo node) Construct an XdmNode as a wrapper around an existing NodeInfo object

Method Summary

Methods

Modifier and Type	Method and Description
Source	asSource() Get a JAXP Source object corresponding to this node, allowing the node to be used as input to transformations or queries.
XdmSequenceIterator	axisIterator(Axis axis) Get an iterator over the nodes reachable from this node via a given axis.
XdmSequenceIterator	axisIterator(Axis axis, QName name) Get an iterator over the nodes reachable from this node via a given axis, selecting only those nodes with a specified name.
boolean	equals(Object other) The equals() relation between two XdmNode objects is true if they both represent the same node.
String	getAttributeValue(QName name) Get the string value of a named attribute of this element
URI	getBaseURI() Get the base URI of this node
int	getColumnNumber() Get the column number of the node in a source document.
URI	getDocumentURI() Get the document URI of this node.
Object	getExternalNode() In the case of an XdmNode that wraps a node in an external object model such as DOM, JDOM, XOM, or DOM4J, get the underlying wrapped node
int	getLineNumber() Get the line number of the node in a source document.
XdmNodeKind	getNodeKind() Get the kind of node.
QName	getNodeName() Get the name of the node, as a QName
XdmNode	getParent() Get the parent of this node
XdmValue	getTypedValue() Get the typed value of this node, as defined in XDM
NodeInfo	getUnderlyingNode() Get the underlying Saxon implementation object representing this node.
int	hashCode() The hashcode is such that two XdmNode instances have the same hashCode if they represent the same node.
String	toString() The toString() method returns a simple XML serialization of the node with defaulted serialization parameters.

Methods inherited from class net.sf.saxon.s9api.XdmItem

asMap, getStringValue, isAtomicValue, size, wrapItem

Methods inherited from class net.sf.saxon.s9api.XdmValue

append, getUnderlyingValue, itemAt, iterator, setValue, wrap

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

XdmNode

public XdmNode(NodeInfo node)

Construct an XdmNode as a wrapper around an existing NodeInfo object

Parameters:

node - the NodeInfo object to be wrapped. This can be retrieved using the getUnderlyingNode() method.

Since:

9.2 (previously a protected constructor)

Method Detail

getNodeKind

public XdmNodeKind getNodeKind()

Get the kind of node.

Returns:

the kind of node, for example XdmNodeKind.ELEMENT or XdmNodeKind.ATTRIBUTE

getNodeName

public QName getNodeName()

Get the name of the node, as a QName

Returns:

the name of the node. In the case of unnamed nodes (for example, text and comment nodes) return null.

getTypedValue

public XdmValue getTypedValue()
                       throws SaxonApiException

Get the typed value of this node, as defined in XDM

Returns:

the typed value. If the typed value is atomic, this will be returned as an instance of XdmAtomicValue

Throws:

SaxonApiException - if an error occurs obtaining the typed value, for example because the node is an element with element-only content

getLineNumber

public int getLineNumber()

Get the line number of the node in a source document. For a document constructed using the document builder, this is available only if the line numbering option was set when the document was built (and then only for element nodes). If the line number is not available, the value -1 is returned. Line numbers will typically be as reported by a SAX parser: this means that the line number for an element node is the line number containing the closing ">" of the start tag.

Returns:

the line number of the node, or -1 if not available.

getColumnNumber

public int getColumnNumber()

Get the column number of the node in a source document. For a document constructed using the document builder, this is available only if the line numbering option was set when the document was built (and then only for element nodes). If the column number is not available, the value -1 is returned. Column numbers will typically be as reported by a SAX parser: this means that the column number for an element node is the position of the closing ">" of the start tag.

Returns:

the column number of the node, or -1 if not available.

asSource

public Source asSource()

Get a JAXP Source object corresponding to this node, allowing the node to be used as input to transformations or queries.

The Source object that is returned will generally be one that is acceptable to Saxon interfaces that expect an instance of javax.xml.transform.Source. However, there is no guarantee that it will be recognized by other products.

In fact, the current implementation always returns an instance of net.sf.saxon.om.NodeInfo.

Returns:

a Source object corresponding to this node

axisIterator

public XdmSequenceIterator axisIterator(Axis axis)

Get an iterator over the nodes reachable from this node via a given axis.

Parameters:

axis - identifies which axis is to be navigated

Returns:

an iterator over the nodes on the specified axis, starting from this node as the context node. The nodes are returned in axis order, that is, in document order for a forwards axis and in reverse document order for a reverse axis.

axisIterator

public XdmSequenceIterator axisIterator(Axis axis,
                               QName name)

Get an iterator over the nodes reachable from this node via a given axis, selecting only those nodes with a specified name.

Parameters:

axis - identifies which axis is to be navigated

name - identifies the name of the nodes to be selected. The selected nodes will be those whose node kind is the principal node kind of the axis (that is, attributes for the attribute axis, namespaces for the namespace axis, and elements for all other axes) whose name matches the specified name.

For example, specify new QName("", "item") to select nodes with local name "item", in no namespace.

Returns:

an iterator over the nodes on the specified axis, starting from this node as the context node. The nodes are returned in axis order, that is, in document order for a forwards axis and in reverse document order for a reverse axis.

getParent

public XdmNode getParent()

Get the parent of this node

Returns:

the parent of this node (a document or element node), or null if this node has no parent.

getAttributeValue

public String getAttributeValue(QName name)

Get the string value of a named attribute of this element

Parameters:

name - the name of the required attribute

Returns:

null if this node is not an element, or if this element has no attribute with the specified name. Otherwise return the string value of the selected attribute node.

getBaseURI

public URI getBaseURI()

Get the base URI of this node

Returns:

the base URI, as defined in the XDM model. The value may be null if no base URI is known for the node, for example if the tree was built from a StreamSource with no associated URI, or if the node has no parent.

Throws:

IllegalStateException - if the base URI property of the underlying node is not a valid URI.

getDocumentURI

public URI getDocumentURI()

Get the document URI of this node.

Returns:

the document URI, as defined in the XDM model. Returns null if no document URI is known

Throws:

IllegalStateException - if the document URI property of the underlying node is not a valid URI.

Since:

9.1

hashCode

public int hashCode()

The hashcode is such that two XdmNode instances have the same hashCode if they represent the same node. Note that the same node might be represented by different XdmNode objects, but these will compare equal.

Overrides:

hashCode in class Object

Returns:

a hashCode representing node identity

equals

public boolean equals(Object other)

The equals() relation between two XdmNode objects is true if they both represent the same node. That is, it corresponds to the "is" operator in XPath.

Overrides:

equals in class Object

Parameters:

other - the object to be compared

Returns:

true if and only if the other object is an XdmNode instance representing the same node

toString

public String toString()

The toString() method returns a simple XML serialization of the node with defaulted serialization parameters.

In the case of an element node, the result will be a well-formed XML document serialized as defined in the W3C XSLT/XQuery serialization specification, using options method="xml", indent="yes", omit-xml-declaration="yes".

In the case of a document node, the result will be a well-formed XML document provided that the document node contains exactly one element child, and no text node children. In other cases it will be a well-formed external general parsed entity.

In the case of an attribute node, the output is a string in the form name="value". The name will use the original namespace prefix.

In the case of a namespace node, the output is a string in the form of a namespace declaration, that is xmlns="uri" or xmlns:pre="uri".

Other nodes, such as text nodes, comments, and processing instructions, are represented as they would appear in lexical XML.

For more control over serialization, use the Serializer class.

Overrides:

toString in class XdmValue

Returns:

a simple XML serialization of the node. Under error conditions the method may return an error message which will always begin with the label "Error: ".

getUnderlyingNode

public NodeInfo getUnderlyingNode()

Get the underlying Saxon implementation object representing this node. This provides access to classes and methods in the Saxon implementation that may be subject to change from one release to another.

Returns:

the underlying implementation object

getExternalNode

public Object getExternalNode()

In the case of an XdmNode that wraps a node in an external object model such as DOM, JDOM, XOM, or DOM4J, get the underlying wrapped node

Returns:

the underlying external node if there is one, or null if this is not an XdmNode that wraps such an external node

Since:

9.1.0.2