The QDomDocument class represents an XML document. More...

Inheritance diagram for QDomDocument:

Public Methods
	QDomDocument ()

	QDomDocument (const QDomDocument &other)

	QDomDocument (const QDomDocumentType &doctype)

	QDomDocument (const QString &name)

	~QDomDocument ()

QDomAttr	createAttribute (const QString &name)

QDomAttr	createAttributeNS (const QString &nsURI, const QString &qName)

QDomCDATASection	createCDATASection (const QString &text)

QDomComment	createComment (const QString &text)

QDomDocumentFragment	createDocumentFragment ()

QDomElement	createElement (const QString &tagName)

QDomElement	createElementNS (const QString &nsURI, const QString &qName)

QDomEntityReference	createEntityReference (const QString &name)

QDomProcessingInstruction	createProcessingInstruction (const QString &target, const QString &data)

QDomText	createTextNode (const QString &text)

QDomDocumentType	doctype () const

QDomElement	documentElement () const

QDomElement	elementById (const QString &elementId)

QDomNodeList	elementsByTagName (const QString &tagname) const

QDomNodeList	elementsByTagNameNS (const QString &nsURI, const QString &localName)

QDomImplementation	implementation () const

QDomNode	importNode (const QDomNode &importedNode, bool deep)

QDomNode::NodeType	nodeType () const

QDomDocument &	operator= (const QDomDocument &other)

bool	setContent (const QByteArray &buffer, QString errorMsg=nullptr, int errorLine=nullptr, int *errorColumn=nullptr)

bool	setContent (const QByteArray &text, bool namespaceProcessing, QString errorMsg=nullptr, int errorLine=nullptr, int *errorColumn=nullptr)

bool	setContent (const QString &text, bool namespaceProcessing, QString errorMsg=nullptr, int errorLine=nullptr, int *errorColumn=nullptr)

bool	setContent (const QString &text, QString errorMsg=nullptr, int errorLine=nullptr, int *errorColumn=nullptr)

bool	setContent (QIODevice device, bool namespaceProcessing, QString errorMsg=nullptr, int errorLine=nullptr, int errorColumn=nullptr)

bool	setContent (QIODevice device, QString errorMsg=nullptr, int errorLine=nullptr, int errorColumn=nullptr)

bool	setContent (QXmlInputSource source, bool namespaceProcessing, QString errorMsg=nullptr, int errorLine=nullptr, int errorColumn=nullptr)

bool	setContent (QXmlInputSource source, QXmlReader reader, QString errorMsg=nullptr, int errorLine=nullptr, int *errorColumn=nullptr)

QByteArray	toByteArray (int indent=1) const

QString	toString (int indent=1) const

Public Methods inherited from QDomNode
	QDomNode ()

	QDomNode (const QDomNode &other)

	~QDomNode ()

QDomNode	appendChild (const QDomNode &newChild)

QDomNamedNodeMap	attributes () const

QDomNodeList	childNodes () const

void	clear ()

QDomNode	cloneNode (bool deep=true) const

int	columnNumber () const

QDomNode	firstChild () const

QDomElement	firstChildElement (const QString &tagName=QString ()) const

bool	hasAttributes () const

bool	hasChildNodes () const

QDomNode	insertAfter (const QDomNode &newChild, const QDomNode &refChild)

QDomNode	insertBefore (const QDomNode &newChild, const QDomNode &refChild)

bool	isAttr () const

bool	isCDATASection () const

bool	isCharacterData () const

bool	isComment () const

bool	isDocument () const

bool	isDocumentFragment () const

bool	isDocumentType () const

bool	isElement () const

bool	isEntity () const

bool	isEntityReference () const

bool	isNotation () const

bool	isNull () const

bool	isProcessingInstruction () const

bool	isSupported (const QString &feature, const QString &version) const

bool	isText () const

QDomNode	lastChild () const

QDomElement	lastChildElement (const QString &tagName=QString ()) const

int	lineNumber () const

QString	localName () const

QDomNode	namedItem (const QString &name) const

QString	namespaceURI () const

QDomNode	nextSibling () const

QDomElement	nextSiblingElement (const QString &tagName=QString ()) const

QString	nodeName () const

NodeType	nodeType () const

QString	nodeValue () const

void	normalize ()

bool	operator!= (const QDomNode &n) const

QDomNode &	operator= (const QDomNode &other)

bool	operator== (const QDomNode &n) const

QDomDocument	ownerDocument () const

QDomNode	parentNode () const

QString	prefix () const

QDomNode	previousSibling () const

QDomElement	previousSiblingElement (const QString &tagName=QString ()) const

QDomNode	removeChild (const QDomNode &oldChild)

QDomNode	replaceChild (const QDomNode &newChild, const QDomNode &oldChild)

void	save (QTextStream &stream, int indent, QDomNode::EncodingPolicy policy=QDomNode::EncodingFromDocument) const

void	setNodeValue (const QString &value)

void	setPrefix (const QString &prefix)

QDomAttr	toAttr () const

QDomCDATASection	toCDATASection () const

QDomCharacterData	toCharacterData () const

QDomComment	toComment () const

QDomDocument	toDocument () const

QDomDocumentFragment	toDocumentFragment () const

QDomDocumentType	toDocumentType () const

QDomElement	toElement () const

QDomEntity	toEntity () const

QDomEntityReference	toEntityReference () const

QDomNotation	toNotation () const

QDomProcessingInstruction	toProcessingInstruction () const

QDomText	toText () const

Friends
class	QDomNode

Additional Inherited Members
Public Types inherited from QDomNode
enum	EncodingPolicy

enum	NodeType

Related Functions inherited from QDomNode
QTextStream &	operator<< (QTextStream &str, const QDomNode &node)

Detailed Description

The QDomDocument class represents an XML document.

The QDomDocument class represents the entire XML document. Conceptually, it is the root of the document tree, and provides the primary access to the document's data.

Since elements, text nodes, comments, processing instructions, etc., can not exist outside the context of a document, the document class also contains the factory functions needed to create these objects. The node objects created have an ownerDocument() function which associates them with the document within whose context they were created. The DOM classes that will be used most often are QDomNode, QDomDocument, QDomElement and QDomText.

The parsed XML is represented internally by a tree of objects that can be accessed using the various QDom classes. All QDom classes only reference objects in the internal tree. The internal objects in the DOM tree will get deleted once the last QDom object referencing them and the QDomDocument itself are deleted.

Creation of elements, text nodes, etc. is done using the various factory functions provided in this class. Using the default constructors of the QDom classes will only result in empty objects that can not be manipulated or inserted into the Document.

The QDomDocument class has several functions for creating document data, for example, createElement(), createTextNode(), createComment(), createCDATASection(), createProcessingInstruction(), createAttribute() and createEntityReference(). Some of these functions have versions that support namespaces, i.e. createElementNS() and createAttributeNS(). The createDocumentFragment() function is used to hold parts of the document; this is useful for manipulating for complex documents.

The entire content of the document is set with setContent(). This function parses the string it is passed as an XML document and creates the DOM tree that represents the document. The root element is available using documentElement(). The textual representation of the document can be obtained using toString().

Note: The DOM tree might end up reserving a lot of memory if the XML document is big. For big XML documents, the QXmlStreamReader or the QXmlQuery classes might be better solutions.

It is possible to insert a node from another document into the document using importNode().

You can obtain a list of all the elements that have a particular tag with elementsByTagName() or with elementsByTagNameNS().

The QDom classes are typically used as follows:

QDomDocument doc("mydocument");
QFile file("mydocument.xml");
 
if (! file.open(QIODevice::ReadOnly))
  return;
 
if (! doc.setContent(&file)) {
  file.close();
  return;
}
file.close();
 
// print the names of all elements that are direct children of the outermost element
QDomElement docElem = doc.documentElement();
 
QDomNode n = docElem.firstChild();
 
while(! n.isNull()) {
  QDomElement e = n.toElement();                    // try to convert the node to an element.
 
  if(! e.isNull()) {
      cout << csPrintable(e.tagName()) << endl;     // the node really is an element.
  }
  n = n.nextSibling();
}
 
// append a new element to the end of the document
QDomElement elem = doc.createElement("img");
elem.setAttribute("src", "myimage.png");
docElem.appendChild(elem);

Once doc and elem go out of scope, the whole internal tree representing the XML document is deleted.

To create a document using DOM use code like this:

QDomDocument doc("MyML");
QDomElement root = doc.createElement("MyML");
doc.appendChild(root);
 
QDomElement tag = doc.createElement("Greeting");
root.appendChild(tag);
 
QDomText t = doc.createTextNode("Hello World");
tag.appendChild(t);
 
QString xml = doc.toString();

For further information about the Document Object Model see the Document Object Model (DOM) Level 1 and Level 2 Core Specifications.

See also: QDomImplementation::createDocumentType()

Constructor & Destructor Documentation

QDomDocument::QDomDocument ( )

Constructs an empty document.

QDomDocument::QDomDocument ( const QString & name )

explicit

Creates a document and sets the name of the document type to name.

QDomDocument::QDomDocument ( const QDomDocumentType & doctype )

explicit

Creates a document with the document type doctype.

See also: QDomImplementation::createDocumentType()

QDomDocument::QDomDocument ( const QDomDocument & other )

Copy constructs a new QDomDocument from other.

QDomDocument::~QDomDocument ( )

Destroys the object and frees its resources.

Method Documentation

QDomAttr QDomDocument::createAttribute ( const QString & name )

Creates a new attribute called name that can be inserted into an element, e.g. using QDomElement::setAttributeNode().

If name is not a valid XML name, the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

See also: createAttributeNS()

QDomAttr QDomDocument::createAttributeNS	(	const QString &	nsURI,
		const QString &	qName
	)

Creates a new attribute with namespace support that can be inserted into an element. The name of the attribute is qName and the namespace URI is nsURI. This function also sets QDomNode::prefix() and QDomNode::localName() to appropriate values (depending on qName).

If qName is not a valid XML name, the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

See also: createAttribute()

QDomCDATASection QDomDocument::createCDATASection ( const QString & text )

Creates a new CDATA section for the string text that can be inserted into the document, e.g. using QDomNode::appendChild().

If value contains characters which can not be stored in a CDATA section, the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

See also: QDomNode::appendChild(), QDomNode::insertBefore(), QDomNode::insertAfter()

QDomComment QDomDocument::createComment ( const QString & text )

Creates a new comment for the string text that can be inserted into the document, e.g. using QDomNode::appendChild().

If value contains characters which can not be stored in an XML comment, the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

See also: QDomNode::appendChild(), QDomNode::insertBefore(), QDomNode::insertAfter()

QDomDocumentFragment QDomDocument::createDocumentFragment ( )

Creates a new document fragment, that can be used to hold parts of the document, e.g. when doing complex manipulations of the document tree.

QDomElement QDomDocument::createElement ( const QString & tagName )

Creates a new element called tagName that can be inserted into the DOM tree, e.g. using QDomNode::appendChild().

If tagName is not a valid XML name, the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

QDomNode::insertAfter()

See also: createElementNS(), QDomNode::appendChild(), QDomNode::insertBefore()

QDomElement QDomDocument::createElementNS	(	const QString &	nsURI,
		const QString &	qName
	)

Creates a new element with namespace support that can be inserted into the DOM tree. The name of the element is qName and the namespace URI is nsURI. This function also sets QDomNode::prefix() and QDomNode::localName() to appropriate values (depending on qName).

If qName is an empty string, returns a null element regardless of whether the invalid data policy is set.

See also: createElement()

QDomEntityReference QDomDocument::createEntityReference ( const QString & name )

Creates a new entity reference called name that can be inserted into the document, e.g. using QDomNode::appendChild().

If name is not a valid XML name, the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

See also: QDomNode::appendChild(), QDomNode::insertBefore(), QDomNode::insertAfter()

QDomProcessingInstruction QDomDocument::createProcessingInstruction	(	const QString &	target,
		const QString &	data
	)

Creates a new processing instruction that can be inserted into the document, e.g. using QDomNode::appendChild(). This function sets the target for the processing instruction to target and the data to data.

If target is not a valid XML name, or data if contains characters which can not appear in a processing instruction, the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

See also: QDomNode::appendChild(), QDomNode::insertBefore(), QDomNode::insertAfter()

QDomText QDomDocument::createTextNode ( const QString & text )

Creates a text node for the string text that can be inserted into the document tree, e.g. using QDomNode::appendChild().

If value contains characters which can not be stored as character data of an XML document (even in the form of character references), the behavior of this function is governed by QDomImplementation::InvalidDataPolicy.

See also: QDomNode::appendChild(), QDomNode::insertBefore(), QDomNode::insertAfter()

QDomDocumentType QDomDocument::doctype ( ) const

Returns the document type of this document.

QDomElement QDomDocument::documentElement ( ) const

Returns the root element of the document.

QDomElement QDomDocument::elementById ( const QString & elementId )

Returns the element whose ID is equal to elementId. If no element with the ID was found, this function returns a null element.

Since the QDomClasses does not know which attributes are element IDs, this function returns always a null element.

QDomNodeList QDomDocument::elementsByTagName ( const QString & tagname ) const

Returns a QDomNodeList, that contains all the elements in the document with the name tagname. The order of the node list is the order they are encountered in a preorder traversal of the element tree.

See also: elementsByTagNameNS(), QDomElement::elementsByTagName()

QDomNodeList QDomDocument::elementsByTagNameNS	(	const QString &	nsURI,
		const QString &	localName
	)

Returns a QDomNodeList that contains all the elements in the document with the local name localName and a namespace URI of nsURI. The order of the node list is the order they are encountered in a preorder traversal of the element tree.

See also: elementsByTagName(), QDomElement::elementsByTagNameNS()

QDomImplementation QDomDocument::implementation ( ) const

Returns a QDomImplementation object.

QDomNode QDomDocument::importNode	(	const QDomNode &	importedNode,
		bool	deep
	)

Imports the node importedNode from another document to this document. importedNode remains in the original document; this function creates a copy that can be used within this document.

This function returns the imported node that belongs to this document. The returned node has no parent. It is not possible to import QDomDocument and QDomDocumentType nodes. In those cases this function returns a null node.

If deep is true, this function imports not only the node importedNode but its whole subtree; if it is false, only the importedNode is imported. The argument deep has no effect on QDomAttr and QDomEntityReference nodes, since the descendants of QDomAttr nodes are always imported and those of QDomEntityReference nodes are never imported.

The behavior of this function is slightly different depending on the node types:

Node Type	Behavior
QDomAttr	The owner element is set to 0 and the specified flag is set to true in the generated attribute. The whole subtree of importedNode is always imported for attribute nodes: deep has no effect.
QDomDocument	Document nodes can not be imported.
QDomDocumentFragment	If deep is true, this function imports the whole document fragment, otherwise it only generates an empty document fragment.
QDomDocumentType	Document type nodes can not be imported.
QDomElement	Attributes for which QDomAttr::specified() is true are also imported, other attributes are not imported. If deep is true, this function also imports the subtree of importedNode, otherwise it imports only the element node (and some attributes, see above).
QDomEntity	Entity nodes can be imported, but at the moment there is no way to use them since the document type is read-only in DOM level 2.
QDomEntityReference	Descendants of entity reference nodes are never imported: deep has no effect.
QDomNotation	Notation nodes can be imported, but at the moment there is no way to use them since the document type is read-only in DOM level 2.
QDomProcessingInstruction	The target and value of the processing instruction is copied to the new node.
QDomText	The text is copied to the new node.
QDomCDATASection	The text is copied to the new node.
QDomComment	The text is copied to the new node.

QDomNode::insertAfter() QDomNode::replaceChild() QDomNode::removeChild() QDomNode::appendChild()

See also: QDomElement::setAttribute(), QDomNode::insertBefore()

QDomNode::NodeType QDomDocument::nodeType ( ) const

inline

Returns DocumentNode.

QDomDocument & QDomDocument::operator= ( const QDomDocument & other )

Copy assigns from other and returns a reference to this object.

bool QDomDocument::setContent	(	const QByteArray &	buffer,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This method reads the XML document from the buffer, returning true if the content was successfully parsed, otherwise returns false. No namespace processing is performed.

bool QDomDocument::setContent	(	const QByteArray &	text,
		bool	namespaceProcessing,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This function parses the XML document from the byte array text and sets it as the content of the document. It tries to detect the encoding of the document as required by the XML specification.

If namespaceProcessing is true, the parser recognizes namespaces in the XML file and sets the prefix name, local name and namespace URI to appropriate values. If namespaceProcessing is false, the parser does no namespace processing when it reads the XML file.

If a parse error occurs, this function returns false and the error message is placed in *errorMsg, the line number in *errorLine and the column number in *errorColumn (unless the associated pointer is set to 0), otherwise this function returns true. The various error messages are described in the QXmlParseException class documentation. Note that, if you want to display these error messages to your application's users, they will be displayed in English unless they are explicitly translated.

If namespaceProcessing is true, the function QDomNode::prefix() returns a string for all elements and attributes. It returns an empty string if the element or attribute has no prefix.

Text nodes consisting only of whitespace are stripped and will not appear in the QDomDocument. If this behavior is not desired, one can use the setContent() overload that allows a QXmlReader to be supplied.

If namespaceProcessing is false, the functions QDomNode::prefix(), QDomNode::localName() and QDomNode::namespaceURI() return an empty string.

Entity references are handled as follows:

References to internal general entities and character entities occurring in the content are included. The result is a QDomText node with the references replaced by their corresponding entity values.
References to parameter entities occurring in the internal subset are included. The result is a QDomDocumentType node which contains entity and notation declarations with the references replaced by their corresponding entity values.
Any general parsed entity reference which is not defined in the internal subset and which occurs in the content is represented as a QDomEntityReference node.
Any parsed entity reference which is not defined in the internal subset and which occurs outside of the content is replaced with an empty string.
Any unparsed entity reference is replaced with an empty string.

QDomNode::prefix() QString::isNull() QString::isEmpty()

Warning: This method is not conditionally thread safe.

See also: QDomNode::namespaceURI(), QDomNode::localName()

bool QDomDocument::setContent	(	const QString &	text,
		bool	namespaceProcessing,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This function reads the XML document from the string text, returning true if the content was successfully parsed, otherwise returns false. Since text is already a Unicode string, no encoding detection is done.

bool QDomDocument::setContent	(	const QString &	text,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This method reads the XML document from the string text, returning true if the content was successfully parsed, otherwise returns false. Since text is already a Unicode string, no encoding detection is performed.

No namespace processing is performed either.

bool QDomDocument::setContent	(	QIODevice *	device,
		bool	namespaceProcessing,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This method reads the XML document from the device and returns true if the content was successfully parsed, otherwise returns false.

bool QDomDocument::setContent	(	QIODevice *	device,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This method reads the XML document from the device, returning true if the content was successfully parsed, otherwise returns false.

No namespace processing is performed.

bool QDomDocument::setContent	(	QXmlInputSource *	source,
		bool	namespaceProcessing,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This method reads the XML document from the QXmlInputSource source, returning true if the content was successfully parsed, otherwise returns false.

bool QDomDocument::setContent	(	QXmlInputSource *	source,
		QXmlReader *	reader,
		QString *	errorMsg = `nullptr`,
		int *	errorLine = `nullptr`,
		int *	errorColumn = `nullptr`
	)

This method reads the XML document from the QXmlInputSource source and parses it with the QXmlReader reader, returning true if the content was successfully parsed, otherwise returns false. This method does not change the features of the reader. If you want to use certain features for parsing you can use this function to set up the reader appropriately.

See also: QXmlSimpleReader

QByteArray QDomDocument::toByteArray ( int indent = 1 ) const

Converts the parsed document back to its textual representation and returns a QByteArray containing the data encoded as UTF-8.

This function uses indent as the amount of space to indent subelements.

See also: toString()

QString QDomDocument::toString ( int indent = 1 ) const

Converts the parsed document back to its textual representation. This function uses indent as the amount of space to indent subelements.

If indent is -1, no whitespace at all is added.

Public Methods

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Method Documentation