The NodeInfo interface represents a node in Saxon's implementation of the XPath 2.0 data model.
Note that several NodeInfo objects may represent the same node. To test node identity, the
method
isSameNodeInfo(NodeInfo)
should be used. An exception to this rule applies for
document nodes, where the correspondence between document nodes and DocumentInfo objects is one to
one. NodeInfo objects are never reused: a given NodeInfo object represents the same node for its entire
lifetime.
This is the primary interface for accessing trees in Saxon, and it forms part of the public
Saxon API. The only subclass of NodeInfo that applications should normally use is
DocumentInfo
,
which represents a document node. Methods that form part of the public API are (since Saxon 8.4)
labelled with a JavaDoc "since" tag: classes and methods that have no such label should not be
regarded as stable interfaces.
The interface represented by this class is at a slightly higher level than the abstraction described
in the W3C data model specification, in that it includes support for the XPath axes, rather than exposing
the lower-level properties (such as "parent" and "children") directly. All navigation within trees,
except for a few convenience methods, is done by following the axes using the
iterateAxis
method.
This allows different implementations of the XPath tree model to implement axis navigation in different ways.
Some implementations may choose to use the helper methods provided in class
Navigator
.
Note that the stability of this interface applies to classes that use the interface,
not to classes that implement it. The interface may be extended in future to add new methods.
New implementations of NodeInfo are advised also to implement the methods in interface
ExtendedNodeInfo, which will be moved into this interface at some time in the future.
ALL_NAMESPACES
public static final int ALL_NAMESPACES
Copy all in-scope namespaces
EMPTY_NAMESPACE_LIST
public static final int[] EMPTY_NAMESPACE_LIST
IS_DTD_TYPE
public static final int IS_DTD_TYPE
Bit setting in the returned type annotation indicating a DTD_derived type on an attribute node
IS_NILLED
public static final int IS_NILLED
Bit setting for use alongside a type annotation indicating that the is-nilled property is set
LOCAL_NAMESPACES
public static final int LOCAL_NAMESPACES
Copy namespaces declared (or undeclared) on this element, but not namespaces inherited from a parent element
NO_NAMESPACES
public static final int NO_NAMESPACES
Don't copy any namespace nodes.
atomize
public Value atomize()
throws XPathException
Get the typed value. The result of this method will always be consistent with the method
Item.getTypedValue()
. However, this method is often more convenient and may be
more efficient, especially in the common case where the value is expected to be a singleton.
- the typed value. This will either be a single AtomicValue or a Value whose items are
atomic values.
compareOrder
public int compareOrder(NodeInfo other)
Determine the relative position of this node and another node, in document order.
The other node must always be in the same tree; the effect of calling this method
when the two nodes are in different trees is undefined. To obtain a global ordering
of nodes, the application should first compare the result of getDocumentNumber(),
and only if the document number is the same should compareOrder() be called.
other
- The other node, whose position is to be compared with this
node
- -1 if this node precedes the other node, +1 if it follows the
other node, or 0 if they are the same node. (In this case,
isSameNode() will always return true, and the two nodes will
produce the same result for generateId())
copy
public void copy(Receiver out,
int whichNamespaces,
boolean copyAnnotations,
int locationId)
throws XPathException
Copy this node to a given Receiver.
This method is primarily for internal use. It should not be considered a stable
part of the Saxon API.
out
- the Receiver to which the node should be copied. It is the caller's
responsibility to ensure that this Receiver is open before the method is called
(or that it is self-opening), and that it is closed after use.whichNamespaces
- in the case of an element, controls
which namespace nodes should be copied. Values are NO_NAMESPACES
,
LOCAL_NAMESPACES
, ALL_NAMESPACES
copyAnnotations
- indicates whether the type annotations
of element and attribute nodes should be copiedlocationId
- If non-zero, identifies the location of the instruction
that requested this copy. If zero, indicates that the location information
for the original node is to be copied; in this case the Receiver must be
a LocationCopier
equals
public boolean equals(Object other)
The equals() method compares nodes for identity. It is defined to give the same result
as isSameNodeInfo().
other
- the node to be compared with this node
- true if this NodeInfo object and the supplied NodeInfo object represent
the same node in the tree.
- 8.7 Previously, the effect of the equals() method was not defined. Callers
should therefore be aware that third party implementations of the NodeInfo interface may
not implement the correct semantics. It is safer to use isSameNodeInfo() for this reason.
The equals() method has been defined because it is useful in contexts such as a Java Set or HashMap.
generateId
public void generateId(FastStringBuffer buffer)
Construct a character string that uniquely identifies this node.
Note: a.isSameNode(b) if and only if generateId(a)==generateId(b)
buffer
- a buffer which will be updated to hold a string
that uniquely identifies this node, across all documents.
- 8.7
Changed in Saxon 8.7 to generate the ID value in a client-supplied buffer
getAttributeValue
public String getAttributeValue(int fingerprint)
Get the string value of a given attribute of this node
fingerprint
- The fingerprint of the attribute name
- the attribute value if it exists, or null if it does not exist. Always returns null
if this node is not an element.
getBaseURI
public String getBaseURI()
Get the Base URI for the node, that is, the URI used for resolving a relative URI contained
in the node. This will be the same as the System ID unless xml:base has been used. Where the
node does not have a base URI of its own, the base URI of its parent node is returned.
- the base URI of the node. This may be null if the base URI is unknown.
getConfiguration
public Configuration getConfiguration()
Get the configuration used to build the tree containing this node.
getDeclaredNamespaces
public int[] getDeclaredNamespaces(int[] buffer)
Get all namespace declarations and undeclarations defined on this element.
This method is intended primarily for internal use. User applications needing
information about the namespace context of a node should use
iterateAxis(Axis.NAMESPACE)
.
(However, not all implementations support the namespace axis, whereas all implementations are
required to support this method.)
buffer
- If this is non-null, and the result array fits in this buffer, then the result
may overwrite the contents of this array, to avoid the cost of allocating a new array on the heap.
- An array of integers representing the namespace declarations and undeclarations present on
this element. For a node other than an element, return null. Otherwise, the returned array is a
sequence of namespace codes, whose meaning may be interpreted by reference to the name pool. The
top half word of each namespace code represents the prefix, the bottom half represents the URI.
If the bottom half is zero, then this is a namespace undeclaration rather than a declaration.
The XML namespace is never included in the list. If the supplied array is larger than required,
then the first unused entry will be set to -1.
For a node other than an element, the method returns null.
getDisplayName
public String getDisplayName()
Get the display name of this node, in the form of a lexical QName.
For elements and attributes this is [prefix:]localname.
For unnamed nodes, it is an empty string.
- The display name of this node. For a node with no name, returns
an empty string.
getDocumentNumber
public int getDocumentNumber()
Get the document number of the document containing this node. For a free-standing
orphan node, just return the hashcode.
- the document number of the document containing this node
getDocumentRoot
public DocumentInfo getDocumentRoot()
Get the root node, if it is a document node.
- the DocumentInfo representing the containing document. If this
node is part of a tree that does not have a document node as its
root, returns null.
getFingerprint
public int getFingerprint()
Get fingerprint. The fingerprint is a coded form of the expanded name
of the node: two nodes
with the same name code have the same namespace URI and the same local name.
The fingerprint contains no information about the namespace prefix. For a name
in the null namespace, the fingerprint is the same as the name code.
- an integer fingerprint; two nodes with the same fingerprint have
the same expanded QName. For unnamed nodes (text nodes, comments, document nodes,
and namespace nodes for the default namespace), returns -1.
getLineNumber
public int getLineNumber()
Get line number. Line numbers are not maintained by default, except for
stylesheets and schema documents. Line numbering can be requested using the
-l option on the command line, or by setting options on the TransformerFactory
or the Configuration before the source document is built.
The granularity of line numbering is normally the element level: for other nodes
such as text nodes and attributes, the line number of the parent element will normally be returned.
In the case of a tree constructed by taking input from a SAX parser, the line number will reflect the
SAX rules: that is, the line number of an element is the line number where the start tag ends. This
may be a little confusing where elements have many attributes spread over multiple lines, or where
single attributes (as can easily happen with XSLT 2.0 stylesheets) occupy several lines.
In the case of a tree constructed by a stylesheet or query, the line number may reflect the line in
the stylesheet or query that caused the node to be constructed.
The line number can be read from within an XPath expression using the Saxon extension function
saxon:line-number()
- the line number of the node in its original source document; or
-1 if not available
getLocalPart
public String getLocalPart()
Get the local part of the name of this node. This is the name after the ":" if any.
- the local part of the name. For an unnamed node, returns "". Unlike the DOM
interface, this returns the full name in the case of a non-namespaced name.
getNameCode
public int getNameCode()
Get name code. The name code is a coded form of the node name: two nodes
with the same name code have the same namespace URI, the same local name,
and the same prefix. By masking the name code with
NamePool.FP_MASK
, you get a
fingerprint: two nodes with the same fingerprint have the same local name
and namespace URI.
- an integer name code, which may be used to obtain the actual node
name from the name pool. For unnamed nodes (text nodes, comments, document nodes,
and namespace nodes for the default namespace), returns -1.
getNamePool
public NamePool getNamePool()
Get the NamePool that holds the namecode for this node
getNodeKind
public int getNodeKind()
Get the kind of node. This will be a value such as
Type.ELEMENT
or
Type.ATTRIBUTE
. There are seven kinds of node: documents, elements, attributes,
text, comments, processing-instructions, and namespaces.
- an integer identifying the kind of node. These integer values are the
same as those used in the DOM
getParent
public NodeInfo getParent()
Get the NodeInfo object representing the parent of this node
- the parent of this node; null if this node has no parent
getPrefix
public String getPrefix()
Get the prefix of the name of the node. This is defined only for elements and attributes.
If the node has no prefix, or for other kinds of node, returns a zero-length string.
- The prefix of the name of the node.
getRoot
public NodeInfo getRoot()
Get the root node of the tree containing this node
- the NodeInfo representing the top-level ancestor of this node.
This will not necessarily be a document node. If this node has no parent,
then the method returns this node.
getStringValue
public String getStringValue()
Return the string value of the node as defined in the XPath data model.
The interpretation of this depends on the type
of node. For an element it is the accumulated character content of the element,
including descendant elements.
This method returns the string value as if the node were untyped. Unlike the string value
accessor in the XPath 2.0 data model, it does not report an error if the element has a complex
type, instead it returns the concatenation of the descendant text nodes as it would if the element
were untyped.
- getStringValue in interface Item
- getStringValue in interface ValueRepresentation
- the string value of the node
getSystemId
public String getSystemId()
Get the System ID for the node. Note this is not the
same as the base URI: the base URI can be modified by xml:base, but
the system ID cannot. The base URI is used primarily for resolving
relative URIs within the content of the document. The system ID is
used primarily in conjunction with a line number, for identifying the
location of elements within the source XML, in particular when errors
are found. For a document node, the System ID represents the value of
the document-uri property as defined in the XDM data model.
- the System Identifier of the entity in the source document
containing the node, or null if not known or not applicable.
getTypeAnnotation
public int getTypeAnnotation()
Get the type annotation of this node, if any. The type annotation is represented as an integer;
this is the fingerprint of the name of the type, as defined in the name pool. Anonymous types
are given a system-defined name. The value of the type annotation can be used to retrieve the
actual schema type definition using the method
Configuration.getSchemaType(int)
.
The bit IS_DTD_TYPE (1<<30) will be set in the case of an attribute node if the type annotation
is one of ID, IDREF, or IDREFS and this is derived from DTD rather than schema validation.
- the type annotation of the node, under the mask NamePool.FP_MASK, and optionally the
bit setting IS_DTD_TYPE in the case of a DTD-derived ID or IDREF/S type (which is treated
as untypedAtomic for the purposes of obtaining the typed value).
The result is undefined for nodes other than elements and attributes.
getURI
public String getURI()
Get the URI part of the name of this node. This is the URI corresponding to the
prefix, or the URI of the default namespace if appropriate.
- The URI of the namespace of this node. For an unnamed node,
or for an element or attribute that is not in a namespace, or for a processing
instruction, returns an empty string.
hasChildNodes
public boolean hasChildNodes()
Determine whether the node has any children.
Note: the result is equivalent to
iterateAxis(Axis.CHILD).next() != null
- True if the node has one or more children
hashCode
public int hashCode()
The hashCode() method obeys the contract for hashCode(): that is, if two objects are equal
(represent the same node) then they must have the same hashCode()
- 8.7 Previously, the effect of the equals() and hashCode() methods was not defined. Callers
should therefore be aware that third party implementations of the NodeInfo interface may
not implement the correct semantics.
isSameNodeInfo
public boolean isSameNodeInfo(NodeInfo other)
Determine whether this is the same node as another node.
Note that two different NodeInfo instances can represent the same conceptual node.
Therefore the "==" operator should not be used to test node identity. The equals()
method should give the same result as isSameNodeInfo(), but since this rule was introduced
late it might not apply to all implementations.
Note: a.isSameNodeInfo(b) if and only if generateId(a)==generateId(b).
This method has the same semantics as isSameNode() in DOM Level 3, but
works on Saxon NodeInfo objects rather than DOM Node objects.
other
- the node to be compared with this node
- true if this NodeInfo object and the supplied NodeInfo object represent
the same node in the tree.
iterateAxis
public AxisIterator iterateAxis(byte axisNumber)
Return an iteration over all the nodes reached by the given axis from this node
axisNumber
- an integer identifying the axis; one of the constants
defined in class Axis
- an AxisIterator that delivers the nodes reached by the axis in
turn. The nodes are returned in axis order (document order for a forwards
axis, reverse document order for a reverse axis).
iterateAxis
public AxisIterator iterateAxis(byte axisNumber,
NodeTest nodeTest)
Return an iteration over all the nodes reached by the given axis from this node
that match a given NodeTest
axisNumber
- an integer identifying the axis; one of the constants
defined in class Axis
nodeTest
- A condition to be satisfied by the returned nodes; nodes
that do not satisfy this condition are not included in the result
- an AxisIterator that delivers the nodes reached by the axis in
turn. The nodes are returned in axis order (document order for a forwards
axis, reverse document order for a reverse axis).