QDomDocument

NAME

SYNOPSIS

#include <qdom.h>

Inherits QDomNode.

Public Members

DESCRIPTION

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., cannot 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 cannot 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().

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( IO_ReadOnly ) )


        return;


    if ( !doc.setContent( &file ) ) {


        file.close();


        return;


    }


    file.close();




    // print out the element 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 << e.tagName() << endl; // the node really is an element.


        }


        n = n.nextSibling();


    }




    // Here we 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 http://www.w3.org/TR/REC-DOM-Level-1/ and http://www.w3.org/TR/DOM-Level-2-Core/. For a more general introduction of the DOM implementation see the QDomDocument documentation.

See also XML.  

MEMBER FUNCTION DOCUMENTATION

QDomDocument::QDomDocument ()

explicit QDomDocument::QDomDocument ( const QString & name )

explicit QDomDocument::QDomDocument ( const QDomDocumentType & doctype )

See also QDomImplementation::createDocumentType().  

QDomDocument::QDomDocument ( const QDomDocument & x )

The data of the copy is shared (shallow copy): modifying one node will also change the other. If you want to make a deep copy, use cloneNode().  

QDomDocument::~QDomDocument ()

QDomAttr QDomDocument::createAttribute ( const QString & name )

See also createAttributeNS().  

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

See also createAttribute().  

QDomCDATASection QDomDocument::createCDATASection ( const QString & value )

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

QDomComment QDomDocument::createComment ( const QString & value )

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

QDomDocumentFragment QDomDocument::createDocumentFragment ()

QDomElement QDomDocument::createElement ( const QString & tagName )

See also createElementNS(), QDomNode::appendChild(), QDomNode::insertBefore(), and QDomNode::insertAfter().  

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

See also createElement().  

QDomEntityReference QDomDocument::createEntityReference ( const QString & name )

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

QDomProcessingInstruction QDomDocument::cre