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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<title>TinyXml: TiXmlHandle Class Reference</title>
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<div class="qindex"><a class="qindex" href="index.html">Main Page</a> | <a class="qindex" href="hierarchy.html">Class Hierarchy</a> | <a class="qindex" href="annotated.html">Class List</a> | <a class="qindex" href="files.html">File List</a> | <a class="qindex" href="functions.html">Class Members</a></div>
<h1>TiXmlHandle Class Reference</h1><!-- doxytag: class="TiXmlHandle" -->A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing.
<a href="#_details">More...</a>
<p>
<code>#include <<a class="el" href="tinyxml_8h-source.html">tinyxml.h</a>></code>
<p>
<a href="classTiXmlHandle-members.html">List of all members.</a><table border="0" cellpadding="0" cellspacing="0">
<tr><td></td></tr>
<tr><td colspan="2"><br><h2>Public Member Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a0"></a><!-- doxytag: member="TiXmlHandle::TiXmlHandle" ref="a0" args="(TiXmlNode *_node)" -->
</td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a0">TiXmlHandle</a> (<a class="el" href="classTiXmlNode.html">TiXmlNode</a> *_node)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Create a handle from any node (at any depth of the tree.) This can be a null pointer. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a1"></a><!-- doxytag: member="TiXmlHandle::TiXmlHandle" ref="a1" args="(const TiXmlHandle &ref)" -->
</td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a1">TiXmlHandle</a> (const <a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> &ref)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Copy constructor. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a3"></a><!-- doxytag: member="TiXmlHandle::FirstChild" ref="a3" args="() const " -->
<a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a3">FirstChild</a> () const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child node. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a4"></a><!-- doxytag: member="TiXmlHandle::FirstChild" ref="a4" args="(const char *value) const " -->
<a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a4">FirstChild</a> (const char *value) const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child node with the given name. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a5"></a><!-- doxytag: member="TiXmlHandle::FirstChildElement" ref="a5" args="() const " -->
<a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a5">FirstChildElement</a> () const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child element. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a6"></a><!-- doxytag: member="TiXmlHandle::FirstChildElement" ref="a6" args="(const char *value) const " -->
<a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a6">FirstChildElement</a> (const char *value) const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child element with the given name. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a7">Child</a> (const char *value, int index) const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child with the given name. <a href="#a7"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a8">Child</a> (int index) const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child. <a href="#a8"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a9">ChildElement</a> (const char *value, int index) const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child element with the given name. <a href="#a9"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a10">ChildElement</a> (int index) const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child element. <a href="#a10"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a15"></a><!-- doxytag: member="TiXmlHandle::Node" ref="a15" args="() const " -->
<a class="el" href="classTiXmlNode.html">TiXmlNode</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a15">Node</a> () const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlNode.html">TiXmlNode</a>. This may return null. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a16"></a><!-- doxytag: member="TiXmlHandle::Element" ref="a16" args="() const " -->
<a class="el" href="classTiXmlElement.html">TiXmlElement</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a16">Element</a> () const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlElement.html">TiXmlElement</a>. This may return null. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a17"></a><!-- doxytag: member="TiXmlHandle::Text" ref="a17" args="() const " -->
<a class="el" href="classTiXmlText.html">TiXmlText</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a17">Text</a> () const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlText.html">TiXmlText</a>. This may return null. <br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="a18"></a><!-- doxytag: member="TiXmlHandle::Unknown" ref="a18" args="() const " -->
<a class="el" href="classTiXmlUnknown.html">TiXmlUnknown</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#a18">Unknown</a> () const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlUnknown.html">TiXmlUnknown</a>. This may return null;. <br></td></tr>
</table>
<hr><a name="_details"></a><h2>Detailed Description</h2>
A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing.
<p>
Note that TiXmlHandle is not part of the TinyXml DOM structure. It is a separate utility class.<p>
Take an example: <div class="fragment"><pre class="fragment"> <Document>
<Element attributeA = "valueA">
<Child attributeB = "value1" />
<Child attributeB = "value2" />
</Element>
<Document>
</pre></div><p>
Assuming you want the value of "attributeB" in the 2nd "Child" element, it's very easy to write a *lot* of code that looks like:<p>
<div class="fragment"><pre class="fragment"> TiXmlElement* root = document.FirstChildElement( "Document" );
if ( root )
{
TiXmlElement* element = root->FirstChildElement( "Element" );
if ( element )
{
TiXmlElement* child = element->FirstChildElement( "Child" );
if ( child )
{
TiXmlElement* child2 = child->NextSiblingElement( "Child" );
if ( child2 )
{
// Finally do something useful.
</pre></div><p>
And that doesn't even cover "else" cases. TiXmlHandle addresses the verbosity of such code. A TiXmlHandle checks for null pointers so it is perfectly safe and correct to use:<p>
<div class="fragment"><pre class="fragment"> TiXmlHandle docHandle( &document );
TiXmlElement* child2 = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", 1 ).Element();
if ( child2 )
{
// do something useful
</pre></div><p>
Which is MUCH more concise and useful.<p>
It is also safe to copy handles - internally they are nothing more than node pointers. <div class="fragment"><pre class="fragment"> TiXmlHandle handleCopy = handle;
</pre></div><p>
What they should not be used for is iteration:<p>
<div class="fragment"><pre class="fragment"> int i=0;
while ( true )
{
TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", i ).Element();
if ( !child )
break;
// do something
++i;
}
</pre></div><p>
It seems reasonable, but it is in fact two embedded while loops. The Child method is a linear walk to find the element, so this code would iterate much more than it needs to. Instead, prefer:<p>
<div class="fragment"><pre class="fragment"> TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).FirstChild( "Child" ).Element();
for( child; child; child=child->NextSiblingElement() )
{
// do something
}
</pre></div>
<p>
<hr><h2>Member Function Documentation</h2>
<a class="anchor" name="a8"></a><!-- doxytag: member="TiXmlHandle::Child" ref="a8" args="(int index) const " --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> TiXmlHandle::Child </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">int </td>
<td class="mdname1" valign="top" nowrap> <em>index</em> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap> const</td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Return a handle to the "index" child.
<p>
The first child is 0, the second 1, etc. </td>
</tr>
</table>
<a class="anchor" name="a7"></a><!-- doxytag: member="TiXmlHandle::Child" ref="a7" args="(const char *value, int index) const " --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> TiXmlHandle::Child </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">const char * </td>
<td class="mdname" nowrap> <em>value</em>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>int </td>
<td class="mdname" nowrap> <em>index</em></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"> const</td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Return a handle to the "index" child with the given name.
<p>
The first child is 0, the second 1, etc. </td>
</tr>
</table>
<a class="anchor" name="a10"></a><!-- doxytag: member="TiXmlHandle::ChildElement" ref="a10" args="(int index) const " --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> TiXmlHandle::ChildElement </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">int </td>
<td class="mdname1" valign="top" nowrap> <em>index</em> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap> const</td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Return a handle to the "index" child element.
<p>
The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted. </td>
</tr>
</table>
<a class="anchor" name="a9"></a><!-- doxytag: member="TiXmlHandle::ChildElement" ref="a9" args="(const char *value, int index) const " --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> TiXmlHandle::ChildElement </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">const char * </td>
<td class="mdname" nowrap> <em>value</em>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>int </td>
<td class="mdname" nowrap> <em>index</em></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"> const</td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
</td>
<td>
<p>
Return a handle to the "index" child element with the given name.
<p>
The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted. </td>
</tr>
</table>
<hr>The documentation for this class was generated from the following file:<ul>
<li><a class="el" href="tinyxml_8h-source.html">tinyxml.h</a></ul>
<hr size="1"><address style="align: right;"><small>Generated on Sat Oct 8 14:15:30 2005 for TinyXml by
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.4 </small></address>
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