# Poco::XML

# class Node

Library: XML
Package: DOM
Header: Poco/DOM/Node.h

## Description

The Node interface is the primary datatype for the entire Document Object Model. It represents a single node in the document tree. While all objects implementing the Node interface expose methods for dealing with children, not all objects implementing the Node interface may have children. For example, Text nodes may not have children, and adding children to such nodes results in a DOMException being raised.

The attributes nodeName, nodeValue and attributes are included as a mechanism to get at node information without casting down to the specific derived interface. In cases where there is no obvious mapping of these attributes for a specific nodeType (e.g., nodeValue for an Element or attributes for a Comment), this returns null. Note that the specialized interfaces may contain additional and more convenient mechanisms to get and set the relevant information.

This implementation differs in some ways from the W3C DOM recommendations. For example, the DOM specifies that some methods can return null strings. Instead of null strings, this implementation always returns empty strings.

## Inheritance

Direct Base Classes: EventTarget

All Base Classes: DOMObject, EventTarget

Known Derived Classes: AbstractContainerNode, AbstractNode, Attr, CDATASection, CharacterData, Comment, Document, DocumentFragment, DocumentType, Element, Entity, EntityReference, Notation, ProcessingInstruction, Text

## Member Summary

Member Functions: appendChild, attributes, childNodes, cloneNode, firstChild, getNodeByPath, getNodeByPathNS, getNodeValue, hasAttributes, hasChildNodes, innerText, insertAfterNP, insertBefore, isSupported, lastChild, localName, namespaceURI, nextSibling, nodeName, nodeType, nodeValue, normalize, ownerDocument, parentNode, prefix, previousSibling, removeChild, replaceChild, setNodeValue

Inherited Functions: addEventListener, autoRelease, dispatchEvent, duplicate, release, removeEventListener

## Types Aliases

### NSMap

using NSMap = Poco::XML::NamespaceSupport;

## Enumerations

### Anonymous

ELEMENT_NODE = 1

The node is an Element.

ATTRIBUTE_NODE

The node is an Attr.

TEXT_NODE

The node is a Text node.

CDATA_SECTION_NODE

The node is a CDATASection.

ENTITY_REFERENCE_NODE

The node is an EntityReference.

ENTITY_NODE

The node is an Entity.

PROCESSING_INSTRUCTION_NODE

The node is a ProcessingInstruction.

COMMENT_NODE

The node is a Comment.

DOCUMENT_NODE

The node is a Document.

DOCUMENT_TYPE_NODE

The node is a DocumentType.

DOCUMENT_FRAGMENT_NODE

The node is a DocumentFragment.

NOTATION_NODE

The node is a Notation.

## Destructor

### ~Node

virtual ~Node();

## Member Functions

### appendChild

virtual Node * appendChild(
Node * newChild
) = 0;

Appends the node newChild to the end of the list of children of this node. If newChild is already in the tree, it is first removed.

### attributes

virtual NamedNodeMap * attributes() const = 0;

Returns a NamedNodeMap containing the attributes of this node (if it is an Element) or null otherwise.

The returned NamedNodeMap must be released with a call to release() when no longer needed.

### childNodes

virtual NodeList * childNodes() const = 0;

Returns a NodeList containing all children of this node.

The returned NodeList must be released with a call to release() when no longer needed.

### cloneNode

virtual Node * cloneNode(
bool deep
) const = 0;

Returns a duplicate of this node, i.e., serves as a generic copy constructor for nodes. The duplicate node has no parent; (parentNode is null.). Cloning an Element copies all attributes and their values, including those generated by the XML processor to represent defaulted attributes, but this method does not copy any text it contains unless it is a deep clone, since the text is contained in a child Text node. Cloning an Attribute directly, as opposed to be cloned as part of an Element cloning operation, returns a specified attribute (specified is true). Cloning any other type of node simply returns a copy of this node. Note that cloning an immutable subtree results in a mutable copy, but the children of an EntityReference clone are readonly. In addition, clones of unspecified Attr nodes are specified. And, cloning Document, DocumentType, Entity, and Notation nodes is implementation dependent.

### firstChild

virtual Node * firstChild() const = 0;

Returns the first child of this node. If there is no such node, this returns null.

### getNodeByPath

virtual Node * getNodeByPath(
const XMLString & path
) const = 0;

Searches a node (element or attribute) based on a simplified XPath expression.

Only simple XPath expressions are supported. These are the slash notation for specifying paths to elements, and the square bracket expression for finding elements by their index, by attribute value, or finding attributes by names.

The slash at the beginning is optional, the evaluation always starts at this element. A double-slash at the beginning recursively searches the entire subtree for the first element.

Examples:

    elem1/elem2/elem3
    /elem1/elem2/elem3
    /elem1/elem2[1]
    /elem1/elem2[@attr1]
    /elem1/elem2[@attr1='value']
    //elem2[@attr1='value']
    //[@attr1='value']

This method is an extension to the W3C Document Object Model.

### getNodeByPathNS

virtual Node * getNodeByPathNS(
const XMLString & path,
const NSMap & nsMap
) const = 0;

Searches a node (element or attribute) based on a simplified XPath expression. The given NSMap must contain mappings from namespace prefixes to namespace URIs for all namespace prefixes used in the path expression.

Only simple XPath expressions are supported. These are the slash notation for specifying paths to elements, and the square bracket expression for finding elements by their index, by attribute value, or finding attributes by names.

The slash at the beginning is optional, the evaluation always starts at this element. A double-slash at the beginning recursively searches the entire subtree for the first element.

Examples:

    /ns1:elem1/ns2:elem2/ns2:elem3
    /ns1:elem1/ns2:elem2[1]
    /ns1:elem1/ns2:elem2[@attr1]
    /ns1:elem1/ns2:elem2[@attr1='value']
    //ns2:elem2[@ns1:attr1='value']
    //[@ns1:attr1='value']

This method is an extension to the W3C Document Object Model.

### getNodeValue

virtual const XMLString & getNodeValue() const = 0;

Returns the value of this node, depending on its type.

### hasAttributes

virtual bool hasAttributes() const = 0;

Returns whether this node (if it is an element) has any attributes.

### hasChildNodes

virtual bool hasChildNodes() const = 0;

This is a convenience method to allow easy determination of whether a node has any children. Returns true if the node has any children, false otherwise.

### innerText

virtual XMLString innerText() const = 0;

Returns a string containing the concatenated values of the node and all its child nodes.

This method is not part of the W3C Document Object Model.

### insertAfterNP

virtual Node * insertAfterNP(
Node * newChild,
Node * refChild
) = 0;

Inserts the node newChild after the existing child node refChild.

If refChild is null, insert newChild at the beginning of the list of children. If newChild is a DocumentFragment object, all of its children are inserted in the same order, after refChild. If the newChild is already in the tree, it is first removed.

### insertBefore

virtual Node * insertBefore(
Node * newChild,
Node * refChild
) = 0;

Inserts the node newChild before the existing child node refChild.

If refChild is null, insert newChild at the end of the list of children. If newChild is a DocumentFragment object, all of its children are inserted in the same order, before refChild. If the newChild is already in the tree, it is first removed.

### isSupported

virtual bool isSupported(
const XMLString & feature,
const XMLString & version
) const = 0;

Tests whether the DOM implementation implements a specific feature and that feature is supported by this node.

### lastChild

virtual Node * lastChild() const = 0;

Returns the last child of this node. If there is no such node, this returns null.

### localName

virtual const XMLString & localName() const = 0;

Returns the local name of the node.

### namespaceURI

virtual const XMLString & namespaceURI() const = 0;

Returns the namespace URI of the node. This is not a computed value that is the result of a namespace lookup based on an examination of the namespace declarations in scope. It is merely the namespace URI given at creation time.

For nodes of any type other than ELEMENT_NODE and ATTRIBUTE_NODE and nodes created with a DOM Level 1 method, such as createElement from the Document interface, this is always the empty string.

### nextSibling

virtual Node * nextSibling() const = 0;

Returns the node immediately following this node. If there is no such node, this returns null.

### nodeName

virtual const XMLString & nodeName() const = 0;

Returns the name of this node, depending on its type.

### nodeType

virtual unsigned short nodeType() const = 0;

Returns a code representing the type of the underlying object.

### nodeValue

const XMLString & nodeValue() const;

Returns the value of this node, depending on its type.

### normalize

virtual void normalize() = 0;

Puts all Text nodes in the full depth of the sub-tree underneath this Node, including attribute nodes, into a "normal" form where only structure (e.g., elements, comments, processing instructions, CDATA sections, and entity references) separates Text nodes, i.e., there are neither adjacent Text nodes nor empty Text nodes. This can be used to ensure that the DOM view of a document is the same as if it were saved and re-loaded, and is useful when operations (such as XPointer lookups) that depend on a particular document tree structure are to be used.

Note: In cases where the document contains CDATASections, the normalize operation alone may not be sufficient, since XPointers do not differentiate between Text nodes and CDATASection nodes.

### ownerDocument

virtual Document * ownerDocument() const = 0;

Returns the Document object associated with this node. This is also the Document object used to create new nodes. When this node is a Document, this is null.

### parentNode

virtual Node * parentNode() const = 0;

The parent of this node. All nodes, except Attr, Document, DocumentFragment, Entity, and Notation may have a parent. However, if a node has just been created and not yet added to the tree, or if it has been removed from the tree, this is null.

### prefix

virtual XMLString prefix() const = 0;

Returns the namespace prefix from the qualified name of the node.

### previousSibling

virtual Node * previousSibling() const = 0;

Returns the node immediately preceding this node. If there is no such node, this returns null.

### removeChild

virtual Node * removeChild(
Node * oldChild
) = 0;

Removes the child node indicated by oldChild from the list of children and returns it.

### replaceChild

virtual Node * replaceChild(
Node * newChild,
Node * oldChild
) = 0;

Replaces the child node oldChild with newChild in the list of children, and returns the oldChild node. If newChild is a DocumentFragment object, oldChild is replaced by all of the DocumentFragment children, which are inserted in the same order. If the newChild is already in the tree, it is first removed.

### setNodeValue

virtual void setNodeValue(
const XMLString & value
) = 0;

Sets the value of this node. Throws an exception if the node is read-only.