<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- qabstractxmlreceiver.cpp --> <title>QAbstractXmlReceiver Class | Qt XML Patterns 5.9</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.9</td><td ><a href="qtxmlpatterns-index.html">Qt XML Patterns</a></td><td ><a href="qtxmlpatterns-module.html">C++ Classes</a></td><td >QAbstractXmlReceiver</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#public-functions">Public Functions</a></li> <li class="level1"><a href="#details">Detailed Description</a></li> <li class="level2"><a href="#xquery-sequences">XQuery Sequences</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">QAbstractXmlReceiver Class</h1> <!-- $$$QAbstractXmlReceiver-brief --> <p>The <a href="qabstractxmlreceiver.html">QAbstractXmlReceiver</a> class provides a callback interface for transforming the output of a <a href="qxmlquery.html">QXmlQuery</a>. <a href="#details">More...</a></p> <!-- @@@QAbstractXmlReceiver --> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QAbstractXmlReceiver></span> </td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += xmlpatterns</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Since:</td><td class="memItemRight bottomAlign"> Qt 4.4</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherited By:</td><td class="memItemRight bottomAlign"> <p><a href="qxmlserializer.html">QXmlSerializer</a></p> </td></tr></table></div><ul> <li><a href="qabstractxmlreceiver-members.html">List of all members, including inherited members</a></li> </ul> <p><b>Note:</b> All functions in this class are reentrant.</p> <a name="public-functions"></a> <h2 id="public-functions">Public Functions</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#QAbstractXmlReceiver">QAbstractXmlReceiver</a></b>()</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#dtor.QAbstractXmlReceiver">~QAbstractXmlReceiver</a></b>()</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#atomicValue">atomicValue</a></b>(const QVariant &<i>value</i>) = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#attribute">attribute</a></b>(const QXmlName &<i>name</i>, const QStringRef &<i>value</i>) = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#characters">characters</a></b>(const QStringRef &<i>value</i>) = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#comment">comment</a></b>(const QString &<i>value</i>) = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#endDocument">endDocument</a></b>() = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#endElement">endElement</a></b>() = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#endOfSequence">endOfSequence</a></b>() = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#namespaceBinding">namespaceBinding</a></b>(const QXmlName &<i>name</i>) = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#processingInstruction">processingInstruction</a></b>(const QXmlName &<i>target</i>, const QString &<i>value</i>) = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#startDocument">startDocument</a></b>() = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#startElement">startElement</a></b>(const QXmlName &<i>name</i>) = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qabstractxmlreceiver.html#startOfSequence">startOfSequence</a></b>() = 0</td></tr> </table></div> <a name="details"></a> <!-- $$$QAbstractXmlReceiver-description --> <div class="descr"> <h2 id="details">Detailed Description</h2> <p>The <a href="qabstractxmlreceiver.html">QAbstractXmlReceiver</a> class provides a callback interface for transforming the output of a <a href="qxmlquery.html">QXmlQuery</a>.</p> <p><a href="qabstractxmlreceiver.html">QAbstractXmlReceiver</a> is an abstract base class that provides a callback interface for receiving an <a href="qabstractxmlreceiver.html#xquery-sequence">XQuery sequence</a>, usually the output of an <a href="qxmlquery.html">QXmlQuery</a>, and transforming that sequence into a structure of your choosing, usually XML. Consider the example:</p> <pre class="cpp"> <span class="type"><a href="qxmlquery.html">QXmlQuery</a></span> query; query<span class="operator">.</span>setQuery(<span class="string">"doc('index.html')/html/body/p[1]"</span>); <span class="type"><a href="qxmlserializer.html">QXmlSerializer</a></span> serializer(query<span class="operator">,</span> myOutputDevice); query<span class="operator">.</span>evaluateTo(<span class="operator">&</span>serializer); </pre> <p>First it constructs a <a href="qxmlquery.html">query</a> that gets the first paragraph from document <code>index.html</code>. Then it constructs an <a href="qxmlserializer.html">XML serializer</a> with the <a href="qxmlquery.html">query</a> and myOutputDevice (Note the <a href="qxmlserializer.html">serializer</a> is an <i>XML receiver</i>, ie a subclass of <a href="qabstractxmlreceiver.html">QAbstractXmlReceiver</a>). Finally, it <a href="qxmlquery.html#evaluateTo">evaluates</a> the <a href="qxmlquery.html">query</a>, producing an ordered sequence of calls to the <a href="qxmlserializer.html">serializer's</a> callback functions. The sequence of callbacks transforms the query output to XML and writes it to myOutputDevice.</p> <p>Although the example uses <a href="qxmlquery.html">QXmlQuery</a> to produce the sequence of callbacks to functions in <a href="qabstractxmlreceiver.html">QAbstractXmlReceiver</a>, you can call the callback functions directly as long as your sequence of calls represents a valid <a href="qabstractxmlreceiver.html#xquery-sequence">XQuery sequence</a>.</p> <a name="xquery-sequence"></a><a name="xquery-sequences"></a> <h3 >XQuery Sequences</h3> <p>An <a href="xmlprocessing.html">XQuery</a> <i>sequence</i> is an ordered collection of zero, one, or many <i>items</i>. Each <i>item</i> is either an <i>atomic value</i> or a <i>node</i>. An <i>atomic value</i> is a simple data value.</p> <p>There are six kinds of <i>nodes</i>.</p> <ul> <li>An <i>Element Node</i> represents an XML element.</li> <li>An <i>Attribute Node</i> represents an XML attribute.</li> <li>A <i>Document Node</i> represents an entire XML document.</li> <li>A <i>Text Node</i> represents character data (element content).</li> <li>A <i>Processing Instruction Node</i> represents an XML processing instruction, which is used in an XML document to tell the application reading the document to perform some action. A typical example is to use a processing instruction to tell the application to use a particular XSLT stylesheet to display the document.</li> <li>And a <i>Comment node</i> represents an XML comment.</li> </ul> <p>The <i>sequence</i> of <i>nodes</i> and <i>atomic values</i> obeys the following rules. Note that <i>Namespace Node</i> refers to a special <i>Attribute Node</i> with name <i>xmlns</i>.</p> <ul> <li>Each <i>node</i> appears in the <i>sequence</i> before its children and their descendants appear.</li> <li>A <i>node</i>'s descendants appear in the <i>sequence</i> before any of its siblings appear.</li> <li>A <i>Document Node</i> represents an entire document. Zero or more <i>Document Nodes</i> can appear in a <i>sequence</i>, but they can only be top level items (i.e., a <i>Document Node</i> can't be a child of another <i>node</i>.</li> <li><i>Namespace Nodes</i> immediately follow the <i>Element Node</i> with which they are associated.</li> <li><i>Attribute Nodes</i> immediately follow the <i>Namespace Nodes</i> of the element with which they are associated, or...</li> <li>If there are no <i>Namespace Nodes</i> following an element, then the <i>Attribute Nodes</i> immediately follow the element.</li> <li>An <i>atomic value</i> can only appear as a top level <i>item</i>, i.e., it can't appear as a child of a <i>node</i>.</li> <li><i>Processing Instruction Nodes</i> do not have children, and their parent is either a <i>Document Node</i> or an <i>Element Node</i>.</li> <li><i>Comment Nodes</i> do not have children, and their parent is either a <i>Document Node</i> or an <i>Element Node</i>.</li> </ul> <p>The <i>sequence</i> of <i>nodes</i> and <i>atomic values</i> is sent to an <a href="qabstractxmlreceiver.html">QAbstractXmlReceiver</a> (<a href="qxmlserializer.html">QXmlSerializer</a> in the example above) as a sequence of calls to the receiver's callback functions. The mapping of callback functions to sequence items is as follows.</p> <ul> <li><a href="qabstractxmlreceiver.html#startDocument">startDocument</a>() and <a href="qabstractxmlreceiver.html#endDocument">endDocument</a>() are called for each <i>Document Node</i> in the <i>sequence</i>. <a href="qabstractxmlreceiver.html#endDocument">endDocument</a>() is not called until all the <i>Document Node's</i> children have appeared in the <i>sequence</i>.</li> <li><a href="qabstractxmlreceiver.html#startElement">startElement</a>() and <a href="qabstractxmlreceiver.html#endElement">endElement</a>() are called for each <i>Element Node</i>. <a href="qabstractxmlreceiver.html#endElement">endElement</a>() is not called until all the <i>Element Node's</i> children have appeared in the <i>sequence</i>.</li> <li><a href="qabstractxmlreceiver.html#attribute">attribute</a>() is called for each <i>Attribute Node</i>.</li> <li><a href="qabstractxmlreceiver.html#comment">comment</a>() is called for each <i>Comment Node</i>.</li> <li><a href="qabstractxmlreceiver.html#characters">characters</a>() is called for each <i>Text Node</i>.</li> <li><a href="qabstractxmlreceiver.html#processingInstruction">processingInstruction</a>() is called for each <i>Processing Instruction Node</i>.</li> <li><a href="qabstractxmlreceiver.html#namespaceBinding">namespaceBinding</a>() is called for each <i>Namespace Node</i>.</li> <li><a href="qabstractxmlreceiver.html#atomicValue">atomicValue</a>() is called for each <i>atomic value</i>.</li> </ul> <p>For a complete explanation of <a href="xmlprocessing.html">XQuery</a> sequences, visit <a href="http://www.w3.org/TR/xpath-datamodel/">XQuery Data Model</a>.</p> </div> <p><b>See also </b><a href="http://www.w3.org/TR/xpath-datamodel/">W3C XQuery 1.0 and XPath 2.0 Data Model (XDM)</a>, <a href="qxmlserializer.html">QXmlSerializer</a>, and <a href="qxmlresultitems.html">QXmlResultItems</a>.</p> <!-- @@@QAbstractXmlReceiver --> <div class="func"> <h2>Member Function Documentation</h2> <!-- $$$QAbstractXmlReceiver[overload1]$$$QAbstractXmlReceiver --> <h3 class="fn" id="QAbstractXmlReceiver"><a name="QAbstractXmlReceiver"></a>QAbstractXmlReceiver::<span class="name">QAbstractXmlReceiver</span>()</h3> <p>Constructs an abstract xml receiver.</p> <!-- @@@QAbstractXmlReceiver --> <!-- $$$~QAbstractXmlReceiver[overload1]$$$~QAbstractXmlReceiver --> <h3 class="fn" id="dtor.QAbstractXmlReceiver"><a name="dtor.QAbstractXmlReceiver"></a><code>[virtual] </code>QAbstractXmlReceiver::<span class="name">~QAbstractXmlReceiver</span>()</h3> <p>Destroys the xml receiver.</p> <!-- @@@~QAbstractXmlReceiver --> <!-- $$$atomicValue[overload1]$$$atomicValueconstQVariant& --> <h3 class="fn" id="atomicValue"><a name="atomicValue"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">atomicValue</span>(const <span class="type">QVariant</span> &<i>value</i>)</h3> <p>This callback is called when an atomic value appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>. The <i>value</i> is a simple data value. It is guaranteed to be valid.</p> <!-- @@@atomicValue --> <!-- $$$attribute[overload1]$$$attributeconstQXmlName&constQStringRef& --> <h3 class="fn" id="attribute"><a name="attribute"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">attribute</span>(const <span class="type"><a href="qxmlname.html">QXmlName</a></span> &<i>name</i>, const <span class="type">QStringRef</span> &<i>value</i>)</h3> <p>This callback is called when an attribute node appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>. <i>name</i> is the <a href="qxmlname.html">attribute name</a> and the <i>value</i> string contains the attribute value.</p> <!-- @@@attribute --> <!-- $$$characters[overload1]$$$charactersconstQStringRef& --> <h3 class="fn" id="characters"><a name="characters"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">characters</span>(const <span class="type">QStringRef</span> &<i>value</i>)</h3> <p>This callback is called when a text node appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>. The <i>value</i> contains the text. Adjacent text nodes may not occur in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>, i.e., this callback must not be called twice in a row.</p> <!-- @@@characters --> <!-- $$$comment[overload1]$$$commentconstQString& --> <h3 class="fn" id="comment"><a name="comment"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">comment</span>(const <span class="type">QString</span> &<i>value</i>)</h3> <p>This callback is called when a comment node appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>. The <i>value</i> is the comment text, which must not contain the string "--".</p> <!-- @@@comment --> <!-- $$$endDocument[overload1]$$$endDocument --> <h3 class="fn" id="endDocument"><a name="endDocument"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">endDocument</span>()</h3> <p>This callback is called when the end of a document node appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>.</p> <!-- @@@endDocument --> <!-- $$$endElement[overload1]$$$endElement --> <h3 class="fn" id="endElement"><a name="endElement"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">endElement</span>()</h3> <p>This callback is called when the end of an element node appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>.</p> <!-- @@@endElement --> <!-- $$$endOfSequence[overload1]$$$endOfSequence --> <h3 class="fn" id="endOfSequence"><a name="endOfSequence"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">endOfSequence</span>()</h3> <p>This callback is called once only, right after the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a> ends.</p> <!-- @@@endOfSequence --> <!-- $$$namespaceBinding[overload1]$$$namespaceBindingconstQXmlName& --> <h3 class="fn" id="namespaceBinding"><a name="namespaceBinding"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">namespaceBinding</span>(const <span class="type"><a href="qxmlname.html">QXmlName</a></span> &<i>name</i>)</h3> <p>This callback is called when a namespace binding is in scope of an element. A namespace is defined by a URI. In the <a href="qxmlname.html">QXmlName</a> <i>name</i>, the value of <a href="qxmlname.html#namespaceUri">QXmlName::namespaceUri</a>() is that URI. The value of <a href="qxmlname.html#prefix">QXmlName::prefix</a>() is the prefix that the URI is bound to. The local name is insignificant and can be an arbitrary value.</p> <!-- @@@namespaceBinding --> <!-- $$$processingInstruction[overload1]$$$processingInstructionconstQXmlName&constQString& --> <h3 class="fn" id="processingInstruction"><a name="processingInstruction"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">processingInstruction</span>(const <span class="type"><a href="qxmlname.html">QXmlName</a></span> &<i>target</i>, const <span class="type">QString</span> &<i>value</i>)</h3> <p>This callback is called when a processing instruction appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>. A processing instruction is used in an XML document to tell the application reading the document to perform some action. A typical example is to use a processing instruction to tell the application to use a particular XSLT stylesheet to process the document.</p> <pre class="cpp"> <?xml-stylesheet type="test/xsl" href="formatter.xsl"?> </pre> <p><i>target</i> is the <a href="qxmlname.html">name</a> of the processing instruction. Its <i>prefix</i> and <i>namespace URI</i> must both be empty. Its <i>local name</i> is the target. In the above example, the name is <i>xml-stylesheet</i>.</p> <p>The <i>value</i> specifies the action to be taken. Note that the <i>value</i> must not contain the string "?>". In the above example, the <i>value</i> is <i>type="test/xsl" href="formatter.xsl</i>.</p> <p>Generally, use of processing instructions should be avoided, because they are not namespace aware and in many contexts are stripped out anyway. Processing instructions can often be replaced with elements from a custom namespace.</p> <!-- @@@processingInstruction --> <!-- $$$startDocument[overload1]$$$startDocument --> <h3 class="fn" id="startDocument"><a name="startDocument"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">startDocument</span>()</h3> <p>This callback is called when a document node appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>.</p> <!-- @@@startDocument --> <!-- $$$startElement[overload1]$$$startElementconstQXmlName& --> <h3 class="fn" id="startElement"><a name="startElement"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">startElement</span>(const <span class="type"><a href="qxmlname.html">QXmlName</a></span> &<i>name</i>)</h3> <p>This callback is called when a new element node appears in the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a>. <i>name</i> is the valid <a href="qxmlname.html">name</a> of the node element.</p> <!-- @@@startElement --> <!-- $$$startOfSequence[overload1]$$$startOfSequence --> <h3 class="fn" id="startOfSequence"><a name="startOfSequence"></a><code>[pure virtual] </code><span class="type">void</span> QAbstractXmlReceiver::<span class="name">startOfSequence</span>()</h3> <p>This callback is called once only, right before the <a href="qabstractxmlreceiver.html#xquery-sequence">sequence</a> begins.</p> <!-- @@@startOfSequence --> </div> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2017 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>