org.dom4j
Interface Node

All Superinterfaces:

java.lang.Cloneable

All Known Subinterfaces:

Attribute, Branch, CDATA, Comment, Document, DocumentType, Element, Entity, CharacterData, ProcessingInstruction, Text

All Known Implementing Classes:

AbstractAttribute, AbstractBranch, AbstractCDATA, AbstractComment, AbstractDocument, AbstractDocumentType, AbstractElement, AbstractEntity, AbstractCharacterData, AbstractNode, AbstractProcessingInstruction, AbstractText, BaseElement, BeanAttribute, BeanElement, DatatypeAttribute, DatatypeElement, DefaultAttribute, DefaultCDATA, DefaultComment, DefaultDocument, DefaultDocumentType, DefaultElement, DefaultEntity, DefaultNamespace, DefaultProcessingInstruction, DefaultText, DOMAttribute, DOMCDATA, DOMComment, DOMDocument, DOMDocumentType, DOMElement, DOMEntityReference, DOMNamespace, DOMProcessingInstruction, DOMText, FlyweightAttribute, FlyweightCDATA, FlyweightComment, FlyweightEntity, FlyweightProcessingInstruction, FlyweightText, IndexedElement, Namespace, NonLazyElement, UserDataAttribute, UserDataElement

public interface Node
extends java.lang.Cloneable

Node defines the polymorphic behavior for all XML nodes in a dom4j tree.

A node can be output as its XML format, can be detached from its position in a document and can have XPath expressions evaluated on itself.

A node may optionally support the parent relationship and may be read only.

Version:

$Revision: 1.31 $

Author:

James Strachan

See Also:

supportsParent(), isReadOnly()

Method Summary

void	accept(Visitor visitor) accept is the method used in the Visitor Pattern.
java.lang.String	asXML() asXML returns the textual XML representation of this node.
Node	asXPathResult(Element parent) asXPathResult returns a version of this node which is capable of being an XPath result.
java.lang.Object	clone() clone will return a deep clone or if this node is read-only then clone will return the same instance.
XPath	createXPath(java.lang.String xpathExpression) createXPath creates an XPath object for the given xpathExpression.
Node	detach() Removes this node from its parent if there is one.
Document	getDocument() getDocument returns the Document that this Node is part of if this node supports the parent relationship.
java.lang.String	getName() getName returns the name of this node.
short	getNodeType() Returns the code according to the type of node.
NodeType	getNodeTypeEnum() Returns the type of this node as constant from NodeType enum.
java.lang.String	getNodeTypeName() Returns the name of the type of this node such as "Document", "Element", "Attribute" or "Text"
Element	getParent() getParent returns the parent Element if this node supports the parent relationship or null if it is the root element or does not support the parent relationship.
java.lang.String	getPath() Returns the XPath expression which will return a node set containing the given node such as /a/b/@c.
java.lang.String	getPath(Element context) Returns the relative XPath expression which will return a node set containing the given node such as a/b/@c.
java.lang.String	getStringValue() Returns the XPath string-value of this node.
java.lang.String	getText() Returns the text of this node.
java.lang.String	getUniquePath() Returns the XPath expression which will return a nodeset of one node which is the current node.
java.lang.String	getUniquePath(Element context) Returns the relative unique XPath expression from the given context which will return a nodeset of one node which is the current node.
boolean	hasContent() hasContent returns true if this node is a Branch (either an Element or a Document) and it contains at least one content node such as a child Element or Text node.
boolean	isReadOnly() isReadOnly returns true if this node is read only and cannot be modified.
boolean	matches(java.lang.String xpathExpression) matches returns true if evaluating the given XPath expression on this node returns a non-empty node set containing this node.
java.lang.Number	numberValueOf(java.lang.String xpathExpression) numberValueOf evaluates an XPath expression and returns the numeric value of the XPath expression if the XPath expression results in a number, or null if the result is not a number.
java.util.List<? extends Node>	selectNodes(java.lang.String xpathExpression) selectNodes evaluates an XPath expression and returns the result as a List of Node instances or String instances depending on the XPath expression.
java.util.List<? extends Node>	selectNodes(java.lang.String xpathExpression, java.lang.String comparisonXPathExpression) selectNodes evaluates an XPath expression then sorts the results using a secondary XPath expression Returns a sorted List of Node instances.
java.util.List<? extends Node>	selectNodes(java.lang.String xpathExpression, java.lang.String comparisonXPathExpression, boolean removeDuplicates) selectNodes evaluates an XPath expression then sorts the results using a secondary XPath expression Returns a sorted List of Node instances.
java.lang.Object	selectObject(java.lang.String xpathExpression) selectObject evaluates an XPath expression and returns the result as an Object.
Node	selectSingleNode(java.lang.String xpathExpression) selectSingleNode evaluates an XPath expression and returns the result as a single Node instance.
void	setDocument(Document document) setDocument sets the document of this node if the parent relationship is supported or does nothing if the parent relationship is not supported.
void	setName(java.lang.String name) Sets the text data of this node or this method will throw an UnsupportedOperationException if it is read-only.
void	setParent(Element parent) setParent sets the parent relationship of this node if the parent relationship is supported or does nothing if the parent relationship is not supported.
void	setText(java.lang.String text) Sets the text data of this node or this method will throw an UnsupportedOperationException if it is read-only.
boolean	supportsParent() supportsParent returns true if this node supports the parent relationship.
java.lang.String	valueOf(java.lang.String xpathExpression) valueOf evaluates an XPath expression and returns the textual representation of the results the XPath string-value of this node.
void	write(java.io.Writer writer) write writes this node as the default XML notation for this node.

Method Detail

supportsParent

boolean supportsParent()

supportsParent returns true if this node supports the parent relationship.

Some XML tree implementations are singly linked and only support downward navigation through children relationships. The default case is that both parent and children relationships are supported though for memory and performance reasons the parent relationship may not be supported.

Returns:

true if this node supports the parent relationship or false it is not supported

getParent

Element getParent()

getParent returns the parent Element if this node supports the parent relationship or null if it is the root element or does not support the parent relationship.

This method is an optional feature and may not be supported for all Node implementations.

Returns:

the parent of this node or null if it is the root of the tree or the parent relationship is not supported.

setParent

void setParent(Element parent)

setParent sets the parent relationship of this node if the parent relationship is supported or does nothing if the parent relationship is not supported.

This method should only be called from inside an Element implementation method and is not intended for general use.

Parameters:

parent - is the new parent of this node.

getDocument

Document getDocument()

getDocument returns the Document that this Node is part of if this node supports the parent relationship.

This method is an optional feature and may not be supported for all Node implementations.

Returns:

the document of this node or null if this feature is not supported or the node is not associated with a Document

setDocument

void setDocument(Document document)

setDocument sets the document of this node if the parent relationship is supported or does nothing if the parent relationship is not supported.

This method should only be called from inside a Document implementation method and is not intended for general use.

Parameters:

document - is the new document of this node.

isReadOnly

boolean isReadOnly()

isReadOnly returns true if this node is read only and cannot be modified. Any attempt to modify a read-only Node will result in an UnsupportedOperationException being thrown.

Returns:

true if this Node is read only and cannot be modified otherwise false.

hasContent

boolean hasContent()

hasContent returns true if this node is a Branch (either an Element or a Document) and it contains at least one content node such as a child Element or Text node.

Returns:

true if this Node is a Branch with a nodeCount() of one or more.

getName

java.lang.String getName()

getName returns the name of this node. This is the XML local name of the element, attribute, entity or processing instruction. For CDATA and Text nodes this method will return null.

Returns:

the XML name of this node

setName

void setName(java.lang.String name)

Sets the text data of this node or this method will throw an UnsupportedOperationException if it is read-only.

Parameters:

name - is the new name of this node

getText

java.lang.String getText()

Returns the text of this node.

Returns:

the text for this node.

setText

void setText(java.lang.String text)

Sets the text data of this node or this method will throw an UnsupportedOperationException if it is read-only.

Parameters:

text - is the new textual value of this node

getStringValue

java.lang.String getStringValue()

Returns the XPath string-value of this node. The behaviour of this method is defined in the XPath specification .

Returns:

the text from all the child Text and Element nodes appended together.

getPath

java.lang.String getPath()

Returns the XPath expression which will return a node set containing the given node such as /a/b/@c. No indexing will be used to restrict the path if multiple elements with the same name occur on the path.

Returns:

the XPath expression which will return a nodeset containing at least this node.

getPath

java.lang.String getPath(Element context)

Returns the relative XPath expression which will return a node set containing the given node such as a/b/@c. No indexing will be used to restrict the path if multiple elements with the same name occur on the path.

Parameters:

context - is the parent context from which the relative path should start. If the context is null or the context is not an ancestor of this node then the path will be absolute and start from the document and so begin with the '/' character.

Returns:

the XPath expression relative to the given context which will return a nodeset containing at least this node.

getUniquePath

java.lang.String getUniquePath()

Returns the XPath expression which will return a nodeset of one node which is the current node. This method will use the XPath index operator to restrict the path if multiple elements with the same name occur on the path.

Returns:

the XPath expression which will return a nodeset containing just this node.

getUniquePath

java.lang.String getUniquePath(Element context)

Returns the relative unique XPath expression from the given context which will return a nodeset of one node which is the current node. This method will use the XPath index operator to restrict the path if multiple elements with the same name occur on the path.

Parameters:

context - is the parent context from which the path should start. If the context is null or the context is not an ancestor of this node then the path will start from the document and so begin with the '/' character.

Returns:

the XPath expression relative to the given context which will return a nodeset containing just this node.

asXML

java.lang.String asXML()

asXML returns the textual XML representation of this node.

Returns:

the XML representation of this node

write

void write(java.io.Writer writer)
           throws java.io.IOException

write writes this node as the default XML notation for this node. If you wish to control the XML output (such as for pretty printing, changing the indentation policy etc.) then please use XMLWriter or its derivations.

Parameters:

writer - is the Writer to output the XML to

Throws:

java.io.IOException - DOCUMENT ME!

getNodeTypeEnum

NodeType getNodeTypeEnum()

Returns the type of this node as constant from NodeType enum.

Returns:

the type of this node

getNodeType

short getNodeType()

Returns the code according to the type of node. This makes processing nodes polymorphically much easier as the switch statement can be used instead of multiple if (instanceof) statements.

Returns:

a W3C DOM complient code for the node type such as ELEMENT_NODE or ATTRIBUTE_NODE

getNodeTypeName

java.lang.String getNodeTypeName()

Returns the name of the type of this node such as "Document", "Element", "Attribute" or "Text"

Returns:

the name of the type of this node

detach

Node detach()

Removes this node from its parent if there is one. If this node is the root element of a document then it is removed from the document as well.

This method is useful if you want to remove a node from its source document and add it to another document. For example

Node node = ...; Element someOtherElement = ...; someOtherElement.add( node.detach() );

Returns:

the node that has been removed from its parent node if any and its document if any.

selectNodes

java.util.List<? extends Node> selectNodes(java.lang.String xpathExpression)

selectNodes evaluates an XPath expression and returns the result as a List of Node instances or String instances depending on the XPath expression.

Parameters:

xpathExpression - is the XPath expression to be evaluated

Returns:

the list of Node or String instances depending on the XPath expression

selectObject

java.lang.Object selectObject(java.lang.String xpathExpression)

selectObject evaluates an XPath expression and returns the result as an Object. The object returned can either be a List of one or more Nodeinstances or a scalar object like a Stringor a Numberinstance depending on the XPath expression.

Parameters:

xpathExpression - is the XPath expression to be evaluated

Returns:

the value of the XPath expression as a Listof Node instances, a Stringor a Numberinstance depending on the XPath expression.

selectNodes

java.util.List<? extends Node> selectNodes(java.lang.String xpathExpression,
                                           java.lang.String comparisonXPathExpression)

selectNodes evaluates an XPath expression then sorts the results using a secondary XPath expression Returns a sorted List of Node instances.

Parameters:

xpathExpression - is the XPath expression to be evaluated

comparisonXPathExpression - is the XPath expression used to compare the results by for sorting

Returns:

the list of Node instances sorted by the comparisonXPathExpression

selectNodes

java.util.List<? extends Node> selectNodes(java.lang.String xpathExpression,
                                           java.lang.String comparisonXPathExpression,
                                           boolean removeDuplicates)

selectNodes evaluates an XPath expression then sorts the results using a secondary XPath expression Returns a sorted List of Node instances.

Parameters:

xpathExpression - is the XPath expression to be evaluated

comparisonXPathExpression - is the XPath expression used to compare the results by for sorting

removeDuplicates - if this parameter is true then duplicate values (using the comparisonXPathExpression) are removed from the result List.

Returns:

the list of Node instances sorted by the comparisonXPathExpression

selectSingleNode

Node selectSingleNode(java.lang.String xpathExpression)

selectSingleNode evaluates an XPath expression and returns the result as a single Node instance.

Parameters:

xpathExpression - is the XPath expression to be evaluated

Returns:

the Node matching the XPath expression

valueOf

java.lang.String valueOf(java.lang.String xpathExpression)

valueOf evaluates an XPath expression and returns the textual representation of the results the XPath string-value of this node. The string-value for a given node type is defined in the XPath specification .

Parameters:

xpathExpression - is the XPath expression to be evaluated

Returns:

the string-value representation of the results of the XPath expression

numberValueOf

java.lang.Number numberValueOf(java.lang.String xpathExpression)

numberValueOf evaluates an XPath expression and returns the numeric value of the XPath expression if the XPath expression results in a number, or null if the result is not a number.

Parameters:

xpathExpression - is the XPath expression to be evaluated

Returns:

the numeric result of the XPath expression or null if the result is not a number.

matches

boolean matches(java.lang.String xpathExpression)

matches returns true if evaluating the given XPath expression on this node returns a non-empty node set containing this node.

This method does not behave like the <xsl:if> element - if you want that behaviour, to evaluate if an XPath expression matches something, then you can use the following code to be equivalent...

if ( node.selectSingleNode( "/some/path" ) != nulll )

Parameters:

xpathExpression - is an XPath expression

Returns:

true if this node is returned by the given XPath expression

createXPath

XPath createXPath(java.lang.String xpathExpression)
                  throws InvalidXPathException

createXPath creates an XPath object for the given xpathExpression. The XPath object allows the variable context to be specified.

Parameters:

xpathExpression - is the XPath expression to be evaluated

Returns:

an XPath object represeting the given expression

Throws:

InvalidXPathException - if the XPath expression is invalid

asXPathResult

Node asXPathResult(Element parent)

asXPathResult returns a version of this node which is capable of being an XPath result. The result of an XPath expression should always support the parent relationship, whether the original XML tree was singly or doubly linked. If the node does not support the parent relationship then a new node will be created which is linked to its parent and returned.

Parameters:

parent - DOCUMENT ME!

Returns:

a Node which supports the parent relationship

accept

void accept(Visitor visitor)

accept is the method used in the Visitor Pattern.

Parameters:

visitor - is the visitor in the Visitor Pattern

clone

java.lang.Object clone()

clone will return a deep clone or if this node is read-only then clone will return the same instance.

Returns:

a deep clone of myself or myself if I am read only.