org.jaxen.dom
Class DocumentNavigator

java.lang.Object
  extended by org.jaxen.DefaultNavigator
      extended by org.jaxen.dom.DocumentNavigator
All Implemented Interfaces:
Serializable, Navigator

public class DocumentNavigator
extends DefaultNavigator

Interface for navigating around the W3C DOM Level 2 object model.

This class is not intended for direct usage, but is used by the Jaxen engine during evaluation.

This class implements the DefaultNavigator interface for the Jaxen XPath library. This adapter allows the Jaxen library to be used to execute XPath queries against any object tree that implements the DOM level 2 interfaces.

Note: DOM level 2 does not include a node representing an XPath namespace node. This navigator will return namespace nodes as instances of the custom NamespaceNode class, and users will have to check result sets to locate and isolate these.

Author:
David Megginson, James Strachan
See Also:
XPath, NamespaceNode, Serialized Form

Constructor Summary
DocumentNavigator()
          Default constructor.
 
Method Summary
 Iterator getAttributeAxisIterator(Object contextNode)
          Get an iterator over all attributes.
 String getAttributeName(Object attribute)
          Get the local name of an attribute.
 String getAttributeNamespaceUri(Object attribute)
          Get the namespace URI of an attribute.
 String getAttributeQName(Object attribute)
          Get the qualified name of an attribute.
 String getAttributeStringValue(Object object)
          Get the string value of an attribute node.
 Iterator getChildAxisIterator(Object contextNode)
          Get an iterator over all of this node's children.
 String getCommentStringValue(Object object)
          Get the string value of a comment node.
 Object getDocument(String uri)
          Use JAXP to load a namespace aware document from a given URI.
 Object getDocumentNode(Object contextNode)
          Get the top-level document node.
 Object getElementById(Object object, String elementId)
          Returns the element whose ID is given by elementId.
 String getElementName(Object element)
          Get the local name of an element.
 String getElementNamespaceUri(Object element)
          Get the namespace URI of an element.
 String getElementQName(Object element)
          Get the qualified name of an element.
 String getElementStringValue(Object object)
          Get the string value of an element node.
 Iterator getFollowingAxisIterator(Object contextNode)
          Get an iterator over all following nodes, depth-first.
 Iterator getFollowingSiblingAxisIterator(Object contextNode)
          Get an iterator over all following siblings.
static Navigator getInstance()
          Get a constant DocumentNavigator for efficiency.
 Iterator getNamespaceAxisIterator(Object contextNode)
          Get an iterator over all declared namespaces.
 String getNamespacePrefix(Object object)
          Get the prefix value of a namespace node.
 String getNamespaceStringValue(Object object)
          Get the string value of a namespace node.
 Iterator getParentAxisIterator(Object contextNode)
          Get a (single-member) iterator over this node's parent.
 Object getParentNode(Object child)
          Return the XPath parent of the supplied DOM node.
 Iterator getPrecedingSiblingAxisIterator(Object contextNode)
          Get an iterator over all preceding siblings.
 String getProcessingInstructionData(Object obj)
          Get the data of a processing instruction node.
 String getProcessingInstructionTarget(Object obj)
          Get the target of a processing instruction node.
 String getTextStringValue(Object object)
          Get the string value of text.
 boolean isAttribute(Object object)
          Test if a node is an attribute.
 boolean isComment(Object object)
          Test if a node is a comment.
 boolean isDocument(Object object)
          Test if a node is a top-level document.
 boolean isElement(Object object)
          Test if a node is an element.
 boolean isNamespace(Object object)
          Test if a node is a namespace.
 boolean isProcessingInstruction(Object object)
          Test if a node is a processing instruction.
 boolean isText(Object object)
          Test if a node is plain text.
 XPath parseXPath(String xpath)
          Returns a parsed form of the given XPath string, which will be suitable for queries on DOM documents.
 String translateNamespacePrefixToUri(String prefix, Object element)
          Translate a namespace prefix to a URI.
 
Methods inherited from class org.jaxen.DefaultNavigator
getAncestorAxisIterator, getAncestorOrSelfAxisIterator, getDescendantAxisIterator, getDescendantOrSelfAxisIterator, getNodeType, getPrecedingAxisIterator, getSelfAxisIterator
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DocumentNavigator

public DocumentNavigator()
Default constructor.

Method Detail

getInstance

public static Navigator getInstance()
Get a constant DocumentNavigator for efficiency.

Returns:
a constant instance of a DocumentNavigator.

getChildAxisIterator

public Iterator getChildAxisIterator(Object contextNode)
Get an iterator over all of this node's children.

Specified by:
getChildAxisIterator in interface Navigator
Overrides:
getChildAxisIterator in class DefaultNavigator
Parameters:
contextNode - the context node for the child axis.
Returns:
a possibly-empty iterator (not null)

getParentAxisIterator

public Iterator getParentAxisIterator(Object contextNode)
Get a (single-member) iterator over this node's parent.

Specified by:
getParentAxisIterator in interface Navigator
Overrides:
getParentAxisIterator in class DefaultNavigator
Parameters:
contextNode - the context node for the parent axis
Returns:
a possibly-empty iterator (not null)

getParentNode

public Object getParentNode(Object child)
Return the XPath parent of the supplied DOM node. XPath has slightly different definition of parent than DOM does. In particular, the parent of an attribute is not null.

Specified by:
getParentNode in interface Navigator
Overrides:
getParentNode in class DefaultNavigator
Parameters:
child - the child node
Returns:
the parent of the specified node; or null if the node does not have a parent
See Also:
Navigator.isDocument(java.lang.Object), Navigator.isElement(java.lang.Object)

getFollowingSiblingAxisIterator

public Iterator getFollowingSiblingAxisIterator(Object contextNode)
Get an iterator over all following siblings.

Specified by:
getFollowingSiblingAxisIterator in interface Navigator
Overrides:
getFollowingSiblingAxisIterator in class DefaultNavigator
Parameters:
contextNode - the context node for the sibling iterator
Returns:
a possibly-empty iterator (not null)

getPrecedingSiblingAxisIterator

public Iterator getPrecedingSiblingAxisIterator(Object contextNode)
Get an iterator over all preceding siblings.

Specified by:
getPrecedingSiblingAxisIterator in interface Navigator
Overrides:
getPrecedingSiblingAxisIterator in class DefaultNavigator
Parameters:
contextNode - the context node for the preceding sibling axis
Returns:
a possibly-empty iterator (not null)

getFollowingAxisIterator

public Iterator getFollowingAxisIterator(Object contextNode)
Get an iterator over all following nodes, depth-first.

Specified by:
getFollowingAxisIterator in interface Navigator
Overrides:
getFollowingAxisIterator in class DefaultNavigator
Parameters:
contextNode - the context node for the following axis
Returns:
a possibly-empty iterator (not null)

getAttributeAxisIterator

public Iterator getAttributeAxisIterator(Object contextNode)
Get an iterator over all attributes.

Specified by:
getAttributeAxisIterator in interface Navigator
Overrides:
getAttributeAxisIterator in class DefaultNavigator
Parameters:
contextNode - the context node for the attribute axis
Returns:
a possibly-empty iterator (not null)

getNamespaceAxisIterator

public Iterator getNamespaceAxisIterator(Object contextNode)
Get an iterator over all declared namespaces.

Note: this iterator is not live: it takes a snapshot and that snapshot remains static during the life of the iterator (i.e. it won't reflect subsequent changes to the DOM).

In the event that the DOM is inconsistent; for instance a pre:foo element is declared by DOM to be in the http://www.a.com/ namespace but also has an xmlns:pre="http://www.b.com" attribute; then only one of the namespaces will be counted. This will be the intrinsic namespace of the Element or Attr object rather than the one provide by the contradictory namespace declaration attribute. In the event of a contradiction between two attributes on the same element--e.g. pre:foo in the http://www.a.com/ namespace and pre:bar in the http://www.b.com/ namespace--it is undefined which namespace will be returned.

Specified by:
getNamespaceAxisIterator in interface Navigator
Overrides:
getNamespaceAxisIterator in class DefaultNavigator
Parameters:
contextNode - the context node for the namespace axis
Returns:
a possibly-empty iterator (not null)

parseXPath

public XPath parseXPath(String xpath)
                 throws SAXPathException
Returns a parsed form of the given XPath string, which will be suitable for queries on DOM documents.

Parameters:
xpath - the XPath expression
Returns:
a parsed form of the given XPath string
Throws:
SAXPathException - if the string is syntactically incorrect
See Also:
XPath

getDocumentNode

public Object getDocumentNode(Object contextNode)
Get the top-level document node.

Specified by:
getDocumentNode in interface Navigator
Overrides:
getDocumentNode in class DefaultNavigator
Parameters:
contextNode - any node in the document
Returns:
the root node
See Also:
Navigator.isDocument(Object)

getElementNamespaceUri

public String getElementNamespaceUri(Object element)
Get the namespace URI of an element.

Parameters:
element - the target node
Returns:
a string (possibly empty) if the node is an element, and null otherwise

getElementName

public String getElementName(Object element)
Get the local name of an element.

Parameters:
element - the target node
Returns:
a string representing the unqualified local name if the node is an element, or null otherwise

getElementQName

public String getElementQName(Object element)
Get the qualified name of an element.

Parameters:
element - the target node
Returns:
a string representing the qualified (i.e. possibly prefixed) name if the argument is an element, or null otherwise

getAttributeNamespaceUri

public String getAttributeNamespaceUri(Object attribute)
Get the namespace URI of an attribute.

Parameters:
attribute - the target node
Returns:
the namespace name of the specified node

getAttributeName

public String getAttributeName(Object attribute)
Get the local name of an attribute.

Parameters:
attribute - the target node
Returns:
a string representing the unqualified local name if the node is an attribute, or null otherwise

getAttributeQName

public String getAttributeQName(Object attribute)
Get the qualified name of an attribute.

Parameters:
attribute - the target node
Returns:
a string representing the qualified (i.e. possibly prefixed) name if the argument is an attribute, or null otherwise

isDocument

public boolean isDocument(Object object)
Test if a node is a top-level document.

Parameters:
object - the target node
Returns:
true if the node is the document root, false otherwise

isNamespace

public boolean isNamespace(Object object)
Test if a node is a namespace.

Parameters:
object - the target node
Returns:
true if the node is a namespace, false otherwise

isElement

public boolean isElement(Object object)
Test if a node is an element.

Parameters:
object - the target node
Returns:
true if the node is an element, false otherwise

isAttribute

public boolean isAttribute(Object object)
Test if a node is an attribute. xmlns and xmlns:pre attributes do not count as attributes for the purposes of XPath.

Parameters:
object - the target node
Returns:
true if the node is an attribute, false otherwise

isComment

public boolean isComment(Object object)
Test if a node is a comment.

Parameters:
object - the target node
Returns:
true if the node is a comment, false otherwise

isText

public boolean isText(Object object)
Test if a node is plain text.

Parameters:
object - the target node
Returns:
true if the node is a text node, false otherwise

isProcessingInstruction

public boolean isProcessingInstruction(Object object)
Test if a node is a processing instruction.

Parameters:
object - the target node
Returns:
true if the node is a processing instruction, false otherwise

getElementStringValue

public String getElementStringValue(Object object)
Get the string value of an element node.

Parameters:
object - the target node
Returns:
the text inside the node and its descendants if the node is an element, null otherwise

getAttributeStringValue

public String getAttributeStringValue(Object object)
Get the string value of an attribute node.

Parameters:
object - the target node
Returns:
the text of the attribute value if the node is an attribute, null otherwise

getTextStringValue

public String getTextStringValue(Object object)
Get the string value of text.

Parameters:
object - the target node
Returns:
the string of text if the node is text, null otherwise

getCommentStringValue

public String getCommentStringValue(Object object)
Get the string value of a comment node.

Parameters:
object - the target node
Returns:
the text of the comment if the node is a comment, null otherwise

getNamespaceStringValue

public String getNamespaceStringValue(Object object)
Get the string value of a namespace node.

Parameters:
object - the target node
Returns:
the namespace URI as a (possibly empty) string if the node is a namespace node, null otherwise

getNamespacePrefix

public String getNamespacePrefix(Object object)
Get the prefix value of a namespace node.

Parameters:
object - the target node
Returns:
the namespace prefix a (possibly empty) string if the node is a namespace node, null otherwise

translateNamespacePrefixToUri

public String translateNamespacePrefixToUri(String prefix,
                                            Object element)
Translate a namespace prefix to a URI.

Specified by:
translateNamespacePrefixToUri in interface Navigator
Overrides:
translateNamespacePrefixToUri in class DefaultNavigator
Parameters:
prefix - the namespace prefix
element - the namespace context
Returns:
the namespace URI bound to the prefix in the scope of element; null if the prefix is not bound
See Also:
NamespaceContext

getDocument

public Object getDocument(String uri)
                   throws FunctionCallException
Use JAXP to load a namespace aware document from a given URI.

Specified by:
getDocument in interface Navigator
Overrides:
getDocument in class DefaultNavigator
Parameters:
uri - the URI of the document to load
Returns:
the new W3C DOM Level 2 Document instance
Throws:
FunctionCallException - containing a nested exception if a problem occurs trying to parse the given document

getProcessingInstructionTarget

public String getProcessingInstructionTarget(Object obj)
Get the target of a processing instruction node.

Specified by:
getProcessingInstructionTarget in interface Navigator
Overrides:
getProcessingInstructionTarget in class DefaultNavigator
Parameters:
obj - the processing instruction
Returns:
the target of the processing instruction
Throws:
ClassCastException - if obj is not a processing instruction

getProcessingInstructionData

public String getProcessingInstructionData(Object obj)
Get the data of a processing instruction node.

Specified by:
getProcessingInstructionData in interface Navigator
Overrides:
getProcessingInstructionData in class DefaultNavigator
Parameters:
obj - the processing instruction
Returns:
the target of the processing instruction
Throws:
ClassCastException - if obj is not a processing instruction

getElementById

public Object getElementById(Object object,
                             String elementId)
Returns the element whose ID is given by elementId. If no such element exists, returns null. Attributes with the name "ID" are not of type ID unless so defined. Attribute types are only known if when the parser understands DTD's or schemas that declare attributes of type ID. When JAXP is used, you must call setValidating(true) on the DocumentBuilderFactory.

Specified by:
getElementById in interface Navigator
Overrides:
getElementById in class DefaultNavigator
Parameters:
object - a node from the document in which to look for the id
elementId - id to look for
Returns:
element whose ID is given by elementId, or null if no such element exists in the document or if the implementation does not know about attribute types
Throws:
ClassCastException - if object is not an org.w3c.dom.Node object
See Also:
DocumentBuilderFactory


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