CopperSpice API  1.7.2
QXmlNodeModelIndex Class Reference

Identifies a node in an XML node model subclassed from QAbstractXmlNodeModel. More...

Public Typedefs

typedef QList< QXmlNodeModelIndex > List
 

Public Types

enum  DocumentOrder
 
enum  NodeKind
 

Public Methods

 QXmlNodeModelIndex ()
 
 QXmlNodeModelIndex (const QXmlNodeModelIndex &other)
 
qint64 additionalData () const
 
qint64 data () const
 
void * internalPointer () const
 
bool isNull () const
 
const QAbstractXmlNodeModelmodel () const
 
bool operator!= (const QXmlNodeModelIndex &other) const
 
bool operator== (const QXmlNodeModelIndex &other) const
 

Friends

class QAbstractXmlNodeModel
 
class QXmlItem
 

Related Functions

These are not member functions

uint qHash (const QXmlNodeModelIndex &index)
 

Detailed Description

The QXmlNodeModelIndex class identifies a node in an XML node model subclassed from QAbstractXmlNodeModel. QXmlNodeModelIndex is an index into an XML node model.

It contains the following:

Because QXmlNodeModelIndex is intentionally a simple class, it does not have member functions for accessing the properties of nodes. For example, it does not have functions for getting a node's name or its list of attributes or child nodes. If you find that you need to retrieve this kind of information from your query results, there are two ways to proceed.

  • Send the output of your XQuery to an XML receiver, or
  • Let your XQuery do all the work to produce the desired result.

The second case is explained by example. Suppose you want to populate a list widget with the values of certain attributes from a set of result elements. You could write an XQuery to return the set of elements, and then you would write the code to iterate over the result elements, get their attributes, and extract the desired string values. But the simpler way is to just augment your XQuery to finding the desired attribute values. Then all you have to do is evaluate the XQuery using the version of QXmlQuery::evaluateTo() that populates a QStringList, which you can send directly to your widget.

QXmlNodeModelIndex does not impose any restrictions on the data value an QXmlNodeModelIndex should contain. The meaning of the data left to the associated node model. Because QXmlNodeModelIndex depends on a particular subclass of QAbstractXmlNodeModel for its existence, the only way you can create an instance of QXmlNodeModelIndex is by asking the node model to create one for you with QAbstractXmlNodeModel::createIndex(). Since that function is protected, it is usually a good idea to write a public function that creates a QXmlNodeModelIndex from arguments that are appropriate for your particular node model.

A default constructed node index is said to be null, i.e., isNull() returns true.

QXmlNodeModelIndex and QAbstractXmlNodeModel follow the same design pattern used for QModelIndex and QAbstractItemModel.

See also
QAbstractXmlNodeModel::kind()

Member Typedef Documentation

Member Enumeration Documentation

Identifies the specific node comparison operator that should be used.

ConstantValueDescription
QXmlNodeModelIndex::Precedes-1 Signifies the &lt;&lt; operator. Test whether the first operand precedes the second in the document.
QXmlNodeModelIndex::Follows1 Signifies the &gt;&gt; operator. Test whether the first operand follows the second in the document.
QXmlNodeModelIndex::Is0 Signifies the is operator. Test whether two nodes have the same node identity.

Identifies a kind of node.

ConstantValueDescription
QXmlNodeModelIndex::Attribute1Identifies an attribute node
QXmlNodeModelIndex::Text64Identifies a text node
QXmlNodeModelIndex::Comment2Identifies a comment node
QXmlNodeModelIndex::Document4Identifies a document node
QXmlNodeModelIndex::Element8Identifies an element node
QXmlNodeModelIndex::Namespace16Identifies a namespace node
QXmlNodeModelIndex::ProcessingInstruction32 Identifies a processing instruction.

Note that the optional XML declaration at very beginning of the XML document is not a processing instruction

See also
QAbstractXmlNodeModel::kind()

Constructor & Destructor Documentation

QXmlNodeModelIndex::QXmlNodeModelIndex ( )
inline

Default constructor. Creates an item that is null.

See also
isNull()
QXmlNodeModelIndex::QXmlNodeModelIndex ( const QXmlNodeModelIndex &  other)
inline

Standard copy constructor. Creates a QXmlNodeModelIndex instance that is a copy of other.

Method Documentation

qint64 QXmlNodeModelIndex::additionalData ( ) const
inline

Returns the second data value. The node index holds two data values. data() returns the first one.

See also
data()
qint64 QXmlNodeModelIndex::data ( ) const
inline

Returns the first data value. The node index holds two data values. additionalData() returns the second one.

See also
additionalData()
void * QXmlNodeModelIndex::internalPointer ( ) const
inline

Returns the first data value as a void* pointer.

See also
additionalData()
bool QXmlNodeModelIndex::isNull ( ) const
inline

Returns true if this QXmlNodeModelIndex is a default constructed value, otherwise false.

A null QXmlNodeModelIndex does not represent any node and can not be used in conjunction with QAbstractXmlNodeModel.

const QAbstractXmlNodeModel * QXmlNodeModelIndex::model ( ) const
inline

Returns the QAbstractXmlNodeModel that this node index refers to. QXmlNodeModelIndex does not own QAbstractXmlNodeModel and does not keep track of its lifetime, so this pointer will dangle if the QAbstractXmlNodeModel is deallocated first.

There is no setter for the node model because instances of QXmlNodeModelIndex instances are only created with QAbstractXmlNodeModel::createIndex().

bool QXmlNodeModelIndex::operator!= ( const QXmlNodeModelIndex &  other) const

Returns true if other is the same node as this.

bool QXmlNodeModelIndex::operator== ( const QXmlNodeModelIndex &  other) const

Returns true if this node is the same as other. This operator does not compare values, children, or names of nodes. It compares node identities, i.e., whether two nodes are from the same document and are found at the exact same place.

Friends And Related Function Documentation

uint qHash ( const QXmlNodeModelIndex &  index)
related

Returns the hash value for index.

The hash is computed on QXmlNodeModelIndex::data(), QXmlNodeModelIndex::additionalData(), and QXmlNodeModelIndex::model(). This means the hash key can be used for node indexes from different node models.