## org.dom4j
Interface Node

All Superinterfaces:
  Cloneable

All Known Subinterfaces:
  Attribute, Branch, CDATA, CharacterData, Comment, Document, DocumentType, Element, Entity, ProcessingInstruction, Text

All Known Implementing Classes:
  AbstractAttribute, AbstractBranch, AbstractCDATA, AbstractCharacterData, AbstractComment, AbstractDocument, AbstractDocumentType, AbstractElement, AbstractEntity, AbstractNode, AbstractProcessingInstruction, AbstractText, FlyweightCDATA, FlyweightComment, FlyweightText

public interface Node
extends 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()`

Field Summary
`static short` `ANY_NODE` Matches Element nodes
`static short` `ATTRIBUTE_NODE` Matches elements nodes
`static short` `CDATA_SECTION_NODE` Matches elements nodes
`static short` `COMMENT_NODE` Matches Comments nodes
`static short` `DOCUMENT_NODE` Matches Document nodes
`static short` `DOCUMENT_TYPE_NODE` Matches DocumentType nodes
`static short` `ELEMENT_NODE` Matches Element nodes
`static short` `ENTITY_REFERENCE_NODE` Matches elements nodes
`static short` `MAX_NODE_TYPE` The maximum number of node types for sizing purposes
`static short` `NAMESPACE_NODE` Matchs a Namespace Node - NOTE this differs from DOM
`static short` `PROCESSING_INSTRUCTION_NODE` Matches ProcessingInstruction
`static short` `TEXT_NODE` Matches elements nodes
`static short` `UNKNOWN_NODE` Does not match any valid node

Method Summary
`void` `accept(Visitor visitor)` `accept` is the method used in the Visitor Pattern.
`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.
`Object` `clone()` `clone` will return a deep clone or if this node is read-only then clone will return the same instance.
`XPath` `createXPath(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.
`String` `getName()` `getName` returns the name of this node.
`short` `getNodeType()` Returns the code according to the type of node.
`String` `getNodeTypeName()` DOCUMENT ME!
`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.
`String` `getPath()` Returns the XPath expression which will return a node set containing the given node such as /a/b/@c.
`String` `getPath(Element context)` Returns the relative XPath expression which will return a node set containing the given node such as a/b/@c.
`String` `getStringValue()` Returns the XPath string-value of this node.
`String` `getText()` Returns the text of this node.
`String` `getUniquePath()` Returns the XPath expression which will return a nodeset of one node which is the current node.
`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(String xpathExpression)` `matches` returns true if evaluating the given XPath expression on this node returns a non-empty node set containing this node.
`Number` `numberValueOf(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.
`List` `selectNodes(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.
`List` `selectNodes(String xpathExpression, String comparisonXPathExpression)` `selectNodes` evaluates an XPath expression then sorts the results using a secondary XPath expression Returns a sorted `List` of `Node` instances.
`List` `selectNodes(String xpathExpression, 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.
`Object` `selectObject(String xpathExpression)` `selectObject` evaluates an XPath expression and returns the result as an `Object`.
`Node` `selectSingleNode(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(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(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.
`String` `valueOf(String xpathExpression)` `valueOf` evaluates an XPath expression and returns the textual representation of the results the XPath string-value of this node.
`void` `write(Writer writer)` `write` writes this node as the default XML notation for this node.

Field Detail

### ANY_NODE

    public static final short ANY_NODE

  Matches Element nodes

  See Also:
    Constant Field Values

### ELEMENT_NODE

    public static final short ELEMENT_NODE

  Matches Element nodes

  See Also:
    Constant Field Values

### ATTRIBUTE_NODE

    public static final short ATTRIBUTE_NODE

  Matches elements nodes

  See Also:
    Constant Field Values

### TEXT_NODE

    public static final short TEXT_NODE

  Matches elements nodes

  See Also:
    Constant Field Values

### CDATA_SECTION_NODE

    public static final short CDATA_SECTION_NODE

  Matches elements nodes

  See Also:
    Constant Field Values

### ENTITY_REFERENCE_NODE

    public static final short ENTITY_REFERENCE_NODE

  Matches elements nodes

  See Also:
    Constant Field Values

### PROCESSING_INSTRUCTION_NODE

    public static final short PROCESSING_INSTRUCTION_NODE

  Matches ProcessingInstruction

  See Also:
    Constant Field Values

### COMMENT_NODE

    public static final short COMMENT_NODE

  Matches Comments nodes

  See Also:
    Constant Field Values

### DOCUMENT_NODE

    public static final short DOCUMENT_NODE

  Matches Document nodes

  See Also:
    Constant Field Values

### DOCUMENT_TYPE_NODE

    public static final short DOCUMENT_TYPE_NODE

  Matches DocumentType nodes

  See Also:
    Constant Field Values

### NAMESPACE_NODE

    public static final short NAMESPACE_NODE

  Matchs a Namespace Node - NOTE this differs from DOM

  See Also:
    Constant Field Values

### UNKNOWN_NODE

    public static final short UNKNOWN_NODE

  Does not match any valid node

  See Also:
    Constant Field Values

### MAX_NODE_TYPE

    public static final short MAX_NODE_TYPE

  The maximum number of node types for sizing purposes

  See Also:
    Constant Field Values

Method Detail

### supportsParent

    public 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

    public 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

    public 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

    public 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

    public 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

    public 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

    public 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

    public 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

    public void setName(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

    public String getText()

  Returns the text of this node.

  Returns:
    the text for this node.

### setText

    public void setText(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

    public 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

    public 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

    public 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

    public 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

    public 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

    public String asXML()

  `asXML` returns the textual XML representation of this node.

  Returns:
    the XML representation of this node

### write

    public void write(Writer writer)
               throws 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:
    `IOException` - DOCUMENT ME!

### getNodeType

    public 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

    public String getNodeTypeName()

  DOCUMENT ME!

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

### detach

    public 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

    public List selectNodes(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

    public Object selectObject(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 `Node`instances or a scalar object like a `String`or a `Number`instance depending on the XPath expression.

  Parameters:
    `xpathExpression` - is the XPath expression to be evaluated
  Returns:
    the value of the XPath expression as a `List`of `Node` instances, a `String`or a `Number`instance depending on the XPath expression.

### selectNodes

    public List selectNodes(String xpathExpression,
                            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

    public List selectNodes(String xpathExpression,
                            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

    public Node selectSingleNode(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

    public String valueOf(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

    public Number numberValueOf(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

    public boolean matches(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

    public XPath createXPath(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

    public 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

    public void accept(Visitor visitor)

  `accept` is the method used in the Visitor Pattern.

  Parameters:
    `visitor` - is the visitor in the Visitor Pattern

### clone

    public 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.

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