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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QHash>
#include "qxmlname.h"
#include "qnamepool_p.h"
#include "qabstractxmlpullprovider_p.h"
QT_BEGIN_NAMESPACE
using namespace QPatternist;
// TODO have example where query selects, and the events for the result are indented
/*!
\internal
\class AbstractXmlPullProvider
\brief The AbstractXmlPullProvider class provides a pull-based stream interface for the XPath Data Model.
\reentrant
\ingroup xml-tools
AbstractXmlPullProvider allows a stream of items from the XPath Data Model -- essentially XML --
to be iterated over. The subclass of AbstractXmlPullProvider provides the events, and the
user calling next() and so on, consumes them. AbstractXmlPullProvider can be considered
a forward-only, non-reversible iterator.
Note that the content the events describes, are not necessarily a well-formed XML document, but
rather an instance of the XPath Data model, to be specific. For instance, maybe a pull provider
returns two atomic values, followed by an element tree, and at the end two document nodes.
If you are subclassing AbstractXmlPullProvider, be careful to correctly implement
the behaviors, as described for the individual members and events.
\sa AbstractXmlPullProvider::Event
*/
/*!
\enum AbstractXmlPullProvider::Event
\value StartOfInput The value AbstractXmlPullProvider::current() returns before the first call to next().
\value AtomicValue an atomic value such as an \c xs:integer, \c xs:hexBinary, or \c xs:dateTime. Atomic values
can only be top level items.
\value StartDocument Signals the start of a document node. Note that a AbstractXmlPullProvider can provide
a sequence of document nodes.
\value EndDocument Signals the end of a document node. StartDocument and EndDocument are always balanced
and always top-level events. For instance, StartDocument can never appear after any StartElement
events that hasn't been balanced by the corresponding amount of EndElement events.
\value StartElement Signals an element start tag.
\value EndElement Signals the end of an element. StartElement and EndElement events are always balanced.
\value Text Signals a text node. Adjacent text nodes cannot occur.
\value ProcessingInstruction A processing instruction. Its name is returned from name(), and its value in stringValue().
\value Comment a comment node. Its value can be retrieved with stingValue().
\value Attribute Signals an attribute node. Attribute events can only appear after Namespace events, or
if no such are sent, after the StartElement. In addition they must appear sequentially,
and each name must be unique. The ordering of attribute events is undefined and insignificant.
\value Namespace Signals a namespace binding. They occur very infrequently and are not needed for attributes
and elements. Namespace events can only appear after the StartElement event. The
ordering of namespace events is undefined and insignificant.
\value EndOfInput When next() is called after the last event, EndOfInput is returned.
\sa AbstractXmlPullProvider::current()
*/
/*!
Constucts a AbstractXmlPullProvider instance.
*/
AbstractXmlPullProvider::AbstractXmlPullProvider()
{
}
/*!
Destructs this AbstractXmlPullProvider.
*/
AbstractXmlPullProvider::~AbstractXmlPullProvider()
{
}
/*!
\fn Event AbstractXmlPullProvider::next() = 0;
Advances this AbstractXmlPullProvider, and returns the new event.
\sa current()
*/
/*!
\fn Event AbstractXmlPullProvider::current() const = 0;
Returns the event that next() returned the last time it was called. It doesn't
alter this AbstractXmlPullProvider.
current() may not modify this AbstractXmlPullProvider's state. Subsequent calls to current()
must return the same value.
\sa AbstractXmlPullProvider::Event
*/
/*!
\fn QName AbstractXmlPullProvider::name() const = 0;
If the current event is StartElement,
EndElement, ProcessingInstruction, Attribute, or Namespace, the node's name is returned.
If the current event is ProcessingInstruction,
the processing instruction target is in in the local name.
If the current event is Namespace, the name's namespace URI is the namespace, and
the local name is the prefix the name is binding to.
In all other cases, an invalid QName is returned.
*/
/*!
\fn QVariant AbstractXmlPullProvider::atomicValue() const = 0;
If current() event is AtomicValue, the atomic value is returned as a QVariant.
In all other cases, this function returns a null QVariant.
*/
/*!
\fn QString AbstractXmlPullProvider::stringValue() const = 0;
If current() is Text, the text node's value is returned.
If the current() event is Comment, its value is returned. The subclasser guarantees
it does not contain the string "-->".
If the current() event is ProcessingInstruction, its data is returned. The subclasser
guarantees the data does not contain the string "?>".
In other cases, it returns a default constructed string.
*/
/*!
\fn QHash<QXmlName, QString> AbstractXmlPullProvider::attributes() = 0;
If the current() is Element, the attributes of the element are returned,
an empty list of attributes otherwise.
*/
QT_END_NAMESPACE
|
