QXmlItem Class Reference

The QXmlItem class contains either an XML node or an atomic value. More...

#include <qabstractxmlnodemodel.h>

Public Types
typedef QAbstractXmlForwardIterator< QXmlItem >	Iterator
	A QAbstractXmlForwardIterator over QXmlItem. More...

Public Functions
bool	isAtomicValue () const
	Returns true if this item is an atomic value. More...
bool	isNode () const
	Returns true if this item is a Node. More...
bool	isNull () const
	Returns true if this QXmlItem is neither a node nor an atomic value. More...
QXmlItem &	operator= (const QXmlItem &other)
	Assigns other to this. More...
	QXmlItem ()
	Constructs a null QXmlItem that is neither a node nor an atomic value. More...
	QXmlItem (const QXmlItem &other)
	The copy constructor constructs a copy of other. More...
	QXmlItem (const QXmlNodeModelIndex &node)
	Constructs a node QXmlItem that is a copy of node. More...
	QXmlItem (const QVariant &atomicValue)
	Constructs an atomic value QXmlItem with atomicValue. More...
QVariant	toAtomicValue () const
	If this QXmlItem represents an atomic value, it is converted to an appropriate QVariant and returned. More...
QXmlNodeModelIndex	toNodeModelIndex () const
	If this QXmlItem represents a node, it returns the item as a QXmlNodeModelIndex. More...
	~QXmlItem ()
	Destructor. More...

Private Functions
bool	internalIsAtomicValue () const
	QXmlItem (const QPatternist::Item &i)

Properties
union {
const QPatternist::AtomicValue *   m_atomicValue
QPatternist::NodeIndexStorage   m_node
QXmlItemPrivate *   m_ptr
};

Friends
class	QPatternist::Item
class	QPatternist::IteratorBridge
class	QPatternist::ToItemMapper
class	QPatternist::ToQXmlItemMapper
class	QPatternist::VariableLoader

Detailed Description

The QXmlItem class contains either an XML node or an atomic value.

Note

This class or function is reentrant.

Since

4.4

In XQuery, all expressions evaluate to a sequence of items, where each item is either an XML node or an atomic value. The query in the following snippet evaluates to sequence of five items.

<aNode/>,
xs:base64Binary("FFFF"),
current-date(),
3e3, (: A floating point value :)
attribute {"name"} {()}

The five items are: An element, an atomic value (binary data encoded in base64), a date, a float, and an attribute.

QXmlItem is the class that represents these XQuery items in the QtXmlPatterns API. A non-null instance of QXmlItem is either a node or an atomic value. Calling isNode() or isAtomicValue() tells you which it is. Atomic values are represented elsewhere in the Qt API as instances of QVariant, and an instance of QXmlItem that represents an atomic value can be converted to a QVariant by calling toAtomicValue(). A QXmlItem that wraps a node is represented elsewhere as an instance of QXmlNodeModelIndex. A node QXmlItem can be converted to a QXmlNodeModelIndex by calling toNodeModelIndex().

A default constructed QXmlItem instance is neither a node nor an atomic value. It is considered null, in which case isNull() returns true.

An instance of QXmlItem will be left dangling if the XML node model it refers to is deleted, if it is a QXmlNodeModelIndex.

Definition at line 380 of file qabstractxmlnodemodel.h.

Typedefs

Iterator

QXmlItem::Iterator

A QAbstractXmlForwardIterator over QXmlItem.

Definition at line 383 of file qabstractxmlnodemodel.h.

Constructors and Destructors

QXmlItem() [1/5]

QXmlItem::QXmlItem

(

)

Constructs a null QXmlItem that is neither a node nor an atomic value.

isNull() returns true for a default constructed instance.

Definition at line 1207 of file qabstractxmlnodemodel.cpp.

{
    m_node.reset();
}

QXmlItem() [2/5]

QXmlItem::QXmlItem

(

const QXmlItem &

other

)

The copy constructor constructs a copy of other.

Definition at line 1220 of file qabstractxmlnodemodel.cpp.

                                        : m_node(other.m_node)
{
    if(internalIsAtomicValue())
        m_atomicValue->ref.ref();
}

QXmlItem() [3/5]

QXmlItem::QXmlItem

(

const QXmlNodeModelIndex &

node

)

Constructs a node QXmlItem that is a copy of node.

See also

isNode()

Definition at line 1263 of file qabstractxmlnodemodel.cpp.

                                                 : m_node(node.m_storage)
{
}

QXmlItem() [4/5]

QXmlItem::QXmlItem

(

const QVariant &

atomicValue

)

Constructs an atomic value QXmlItem with atomicValue.

See also

isAtomicValue()

Definition at line 1231 of file qabstractxmlnodemodel.cpp.

{
    m_node.reset();
    if(atomicValue.isNull())
    {
        /* Then we behave just like the default constructor. */
        return;
    }

    /*
      We can't assign directly to m_atomicValue, because the
      temporary will self-destruct before we've ref'd it.
    */
    const QPatternist::Item temp(QPatternist::AtomicValue::toXDM(atomicValue));

    if(temp)
    {
        temp.asAtomicValue()->ref.ref();
        m_node.model = reinterpret_cast<const QAbstractXmlNodeModel *>(~0);
        m_atomicValue = temp.asAtomicValue();
    }
    else
    {
        m_atomicValue = 0;
    }
}

~QXmlItem()

QXmlItem::~QXmlItem

(

)

Destructor.

Definition at line 1271 of file qabstractxmlnodemodel.cpp.

{
    if(internalIsAtomicValue() && !m_atomicValue->ref.deref())
        delete m_atomicValue;
}

QXmlItem() [5/5]

QXmlItem::QXmlItem ( const QPatternist::Item &  i )

inlineprivate

Definition at line 524 of file qitem_p.h.

                                                      : m_node(i.node)
    {
        if(isAtomicValue())
            m_atomicValue->ref.ref();
    }

Functions

internalIsAtomicValue()

bool QXmlItem::internalIsAtomicValue ( ) const

inlineprivate

Definition at line 1212 of file qabstractxmlnodemodel.cpp.

Referenced by isAtomicValue(), operator=(), QXmlItem(), and ~QXmlItem().

{
    return m_node.model == reinterpret_cast<QAbstractXmlNodeModel *>(~0);
}

isAtomicValue()

bool QXmlItem::isAtomicValue

(

)

const

Returns true if this item is an atomic value.

Returns false if it is a node or null.

See also

isNull(), isNode()

Definition at line 1320 of file qabstractxmlnodemodel.cpp.

Referenced by QPatternist::VariableLoader::isSameType(), QPatternist::AtomicValue::qtToXDMType(), QXmlItem(), and toAtomicValue().

{
    return internalIsAtomicValue();
}

isNode()

bool QXmlItem::isNode

(

)

const

Returns true if this item is a Node.

Returns false if it is an atomic value or null.

See also

isNull(), isAtomicValue()

Definition at line 1309 of file qabstractxmlnodemodel.cpp.

Referenced by QPatternist::VariableLoader::isSameType(), QPatternist::AtomicValue::qtToXDMType(), and toNodeModelIndex().

{
    return QPatternist::Item::fromPublic(*this).isNode();
}

isNull()

bool QXmlItem::isNull

(

)

const

Returns true if this QXmlItem is neither a node nor an atomic value.

Default constructed instances of QXmlItem are null.

Definition at line 1363 of file qabstractxmlnodemodel.cpp.

Referenced by QXmlQuery::bindVariable(), QXmlQueryPrivate::dynamicContext(), QPatternist::FieldNode::isEmpty(), qIsForwardIteratorEnd(), QPatternist::AtomicValue::qtToXDMType(), QPatternist::XsdValidatingInstanceReader::selectNodeSets(), and QXmlQueryPrivate::staticContext().

{
    return !m_node.model;
}

operator=()

QXmlItem & QXmlItem::operator=

(

const QXmlItem &

other

)

Assigns other to this.

Definition at line 1287 of file qabstractxmlnodemodel.cpp.

{
    if(m_node != other.m_node)
    {
        if(internalIsAtomicValue() && !m_atomicValue->ref.deref())
            delete m_atomicValue;

        m_node = other.m_node;

        if(internalIsAtomicValue())
            m_atomicValue->ref.ref();
    }

    return *this;
}

toAtomicValue()

QVariant QXmlItem::toAtomicValue

(

)

const

If this QXmlItem represents an atomic value, it is converted to an appropriate QVariant and returned.

If this QXmlItem is not an atomic value, the return value is a default constructed QVariant. You can call isAtomicValue() to test whether the item is an atomic value.

See also

isAtomicValue()

Definition at line 1334 of file qabstractxmlnodemodel.cpp.

Referenced by QDeclarativeXmlQueryEngine::doQueryJob(), QPatternist::VariableLoader::isSameType(), and QPatternist::AtomicValue::qtToXDMType().

{
    if(isAtomicValue())
        return QPatternist::AtomicValue::toQt(m_atomicValue);
    else
        return QVariant();
}

toNodeModelIndex()

QXmlNodeModelIndex QXmlItem::toNodeModelIndex

(

)

const

If this QXmlItem represents a node, it returns the item as a QXmlNodeModelIndex.

If this QXmlItem is not a node, the return value is undefined. You can call isNode() to test whether the item is a node.

See also

isNode()

Definition at line 1350 of file qabstractxmlnodemodel.cpp.

Referenced by QPatternist::XsdInstanceReader::convertToQName(), QPatternist::TargetNode::operator==(), QPatternist::qHash(), QPatternist::XsdValidatingInstanceReader::read(), and QPatternist::XsdValidatingInstanceReader::validateKeyIdentityConstraint().

{
    if(isNode())
        return reinterpret_cast<const QXmlNodeModelIndex &>(m_node);
    else
        return QXmlNodeModelIndex();
}

Friends and Related Functions

QPatternist::Item

friend class QPatternist::Item

friend

Definition at line 404 of file qabstractxmlnodemodel.h.

QPatternist::IteratorBridge

friend class QPatternist::IteratorBridge

friend

Definition at line 400 of file qabstractxmlnodemodel.h.

QPatternist::ToItemMapper

friend class QPatternist::ToItemMapper

friend

Definition at line 403 of file qabstractxmlnodemodel.h.

QPatternist::ToQXmlItemMapper

friend class QPatternist::ToQXmlItemMapper

friend

Definition at line 402 of file qabstractxmlnodemodel.h.

QPatternist::VariableLoader

friend class QPatternist::VariableLoader

friend

Definition at line 401 of file qabstractxmlnodemodel.h.

Properties

@371

union { ... }

m_atomicValue

const QPatternist::AtomicValue* QXmlItem::m_atomicValue

Definition at line 416 of file qabstractxmlnodemodel.h.

Referenced by operator=(), QXmlItem(), toAtomicValue(), and ~QXmlItem().

m_node

QPatternist::NodeIndexStorage QXmlItem::m_node

Definition at line 412 of file qabstractxmlnodemodel.h.

Referenced by QPatternist::Item::fromPublic(), isNull(), operator=(), QXmlItem(), and toNodeModelIndex().

m_ptr

QXmlItemPrivate* QXmlItem::m_ptr

Definition at line 417 of file qabstractxmlnodemodel.h.

---

The documentation for this class was generated from the following files:

• /src/xmlpatterns/api/qabstractxmlnodemodel.h
• /src/xmlpatterns/api/qabstractxmlnodemodel.cpp
• /src/xmlpatterns/data/qitem_p.h