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TiXmlHandle Class Reference

#include <tinyxml.h>

List of all members.

Public Member Functions

 TiXmlHandle (TiXmlNode *_node)
 Create a handle from any node (at any depth of the tree.) This can be a null pointer.
 TiXmlHandle (const TiXmlHandle &ref)
 Copy constructor.
TiXmlHandle operator= (const TiXmlHandle &ref)
TiXmlHandle FirstChild () const
 Return a handle to the first child node.
TiXmlHandle FirstChild (const char *value) const
 Return a handle to the first child node with the given name.
TiXmlHandle FirstChildElement () const
 Return a handle to the first child element.
TiXmlHandle FirstChildElement (const char *value) const
 Return a handle to the first child element with the given name.
TiXmlHandle Child (const char *value, int index) const
TiXmlHandle Child (int index) const
TiXmlHandle ChildElement (const char *value, int index) const
TiXmlHandle ChildElement (int index) const
TiXmlHandle FirstChild (const std::string &_value) const
TiXmlHandle FirstChildElement (const std::string &_value) const
TiXmlHandle Child (const std::string &_value, int index) const
TiXmlHandle ChildElement (const std::string &_value, int index) const
TiXmlNode * ToNode () const
TiXmlElement * ToElement () const
TiXmlText * ToText () const
TiXmlUnknown * ToUnknown () const
TiXmlNode * Node () const
TiXmlElement * Element () const
TiXmlText * Text () const
TiXmlUnknown * Unknown () const

Private Attributes

TiXmlNode * node

Detailed Description

A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. Note that TiXmlHandle is not part of the TinyXml DOM structure. It is a separate utility class.

Take an example: 

	<Document>
		<Element attributeA = "valueA">
			<Child attributeB = "value1" />
			<Child attributeB = "value2" />
		</Element>
	<Document>

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:

	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.

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:

	TiXmlHandle docHandle( &document );
	TiXmlElement* child2 = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", 1 ).ToElement();
	if ( child2 )
	{
		// do something useful

Which is MUCH more concise and useful.

It is also safe to copy handles - internally they are nothing more than node pointers. 

	TiXmlHandle handleCopy = handle;

What they should not be used for is iteration:

	int i=0; 
	while ( true )
	{
		TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", i ).ToElement();
		if ( !child )
			break;
		// do something
		++i;
	}

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:

	TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).FirstChild( "Child" ).ToElement();

	for( child; child; child=child->NextSiblingElement() )
	{
		// do something
	}

Definition at line 1613 of file tinyxml.h.

Constructor & Destructor Documentation

TiXmlHandle::TiXmlHandle (  TiXmlNode *  _node  )  [inline]
 

Create a handle from any node (at any depth of the tree.) This can be a null pointer.

Definition at line 1617 of file tinyxml.h.

Referenced by Child(), ChildElement(), FirstChild(), and FirstChildElement().

01617 { this->node = _node; }

TiXmlHandle::TiXmlHandle (  const TiXmlHandle &  ref  )  [inline]
 

Copy constructor.

Definition at line 1619 of file tinyxml.h.

References node.

01619 { this->node = ref.node; }

Member Function Documentation

TiXmlHandle TiXmlHandle::Child (  const std::string &  _value,
int  index
)  const [inline]
 

Definition at line 1654 of file tinyxml.h.

01654 { return Child( _value.c_str(), index ); }

TiXmlHandle TiXmlHandle::Child (  int  index  )  const
 

Return a handle to the "index" child. The first child is 0, the second 1, etc.

Definition at line 1664 of file tinyxml.cpp.

References TiXmlNode::FirstChild(), TiXmlNode::NextSibling(), node, and TiXmlHandle().

01665 {
01666         if ( node )
01667         {
01668                 int i;
01669                 TiXmlNode* child = node->FirstChild();
01670                 for (   i=0;
01671                                 child && i<count;
01672                                 child = child->NextSibling(), ++i )
01673                 {
01674                         // nothing
01675                 }
01676                 if ( child )
01677                         return TiXmlHandle( child );
01678         }
01679         return TiXmlHandle( 0 );
01680 }

TiXmlHandle TiXmlHandle::Child (  const char *  value,
int  index
)  const
 

Return a handle to the "index" child with the given name. The first child is 0, the second 1, etc.

Definition at line 1683 of file tinyxml.cpp.

References TiXmlNode::FirstChild(), TiXmlNode::NextSibling(), node, and TiXmlHandle().

01684 {
01685         if ( node )
01686         {
01687                 int i;
01688                 TiXmlNode* child = node->FirstChild( value );
01689                 for (   i=0;
01690                                 child && i<count;
01691                                 child = child->NextSibling( value ), ++i )
01692                 {
01693                         // nothing
01694                 }
01695                 if ( child )
01696                         return TiXmlHandle( child );
01697         }
01698         return TiXmlHandle( 0 );
01699 }

TiXmlHandle TiXmlHandle::ChildElement (  const std::string &  _value,
int  index
)  const [inline]
 

Definition at line 1655 of file tinyxml.h.

01655 { return ChildElement( _value.c_str(), index ); }

TiXmlHandle TiXmlHandle::ChildElement (  int  index  )  const
 

Return a handle to the "index" child element. The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.

Definition at line 1702 of file tinyxml.cpp.

References TiXmlNode::FirstChildElement(), TiXmlNode::NextSiblingElement(), node, and TiXmlHandle().

01703 {
01704         if ( node )
01705         {
01706                 int i;
01707                 TiXmlElement* child = node->FirstChildElement();
01708                 for (   i=0;
01709                                 child && i<count;
01710                                 child = child->NextSiblingElement(), ++i )
01711                 {
01712                         // nothing
01713                 }
01714                 if ( child )
01715                         return TiXmlHandle( child );
01716         }
01717         return TiXmlHandle( 0 );
01718 }

TiXmlHandle TiXmlHandle::ChildElement (  const char *  value,
int  index
)  const
 

Return a handle to the "index" child element with the given name. The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.

Definition at line 1721 of file tinyxml.cpp.

References TiXmlNode::FirstChildElement(), TiXmlNode::NextSiblingElement(), node, and TiXmlHandle().

01722 {
01723         if ( node )
01724         {
01725                 int i;
01726                 TiXmlElement* child = node->FirstChildElement( value );
01727                 for (   i=0;
01728                                 child && i<count;
01729                                 child = child->NextSiblingElement( value ), ++i )
01730                 {
01731                         // nothing
01732                 }
01733                 if ( child )
01734                         return TiXmlHandle( child );
01735         }
01736         return TiXmlHandle( 0 );
01737 }

TiXmlElement* TiXmlHandle::Element (   )  const [inline]
 

Deprecated:
use ToElement. Return the handle as a TiXmlElement. This may return null.

Definition at line 1678 of file tinyxml.h.

01678 { return ToElement(); }

TiXmlHandle TiXmlHandle::FirstChild (  const std::string &  _value  )  const [inline]
 

Definition at line 1651 of file tinyxml.h.

01651 { return FirstChild( _value.c_str() ); }

TiXmlHandle TiXmlHandle::FirstChild (  const char *  value  )  const
 

Return a handle to the first child node with the given name.

Definition at line 1628 of file tinyxml.cpp.

References TiXmlNode::FirstChild(), node, and TiXmlHandle().

01629 {
01630         if ( node )
01631         {
01632                 TiXmlNode* child = node->FirstChild( value );
01633                 if ( child )
01634                         return TiXmlHandle( child );
01635         }
01636         return TiXmlHandle( 0 );
01637 }

TiXmlHandle TiXmlHandle::FirstChild (   )  const
 

Return a handle to the first child node.

Definition at line 1616 of file tinyxml.cpp.

References TiXmlNode::FirstChild(), node, and TiXmlHandle().

01617 {
01618         if ( node )
01619         {
01620                 TiXmlNode* child = node->FirstChild();
01621                 if ( child )
01622                         return TiXmlHandle( child );
01623         }
01624         return TiXmlHandle( 0 );
01625 }

TiXmlHandle TiXmlHandle::FirstChildElement (  const std::string &  _value  )  const [inline]
 

Definition at line 1652 of file tinyxml.h.

01652 { return FirstChildElement( _value.c_str() ); }

TiXmlHandle TiXmlHandle::FirstChildElement (  const char *  value  )  const
 

Return a handle to the first child element with the given name.

Definition at line 1652 of file tinyxml.cpp.

References TiXmlNode::FirstChildElement(), node, and TiXmlHandle().

01653 {
01654         if ( node )
01655         {
01656                 TiXmlElement* child = node->FirstChildElement( value );
01657                 if ( child )
01658                         return TiXmlHandle( child );
01659         }
01660         return TiXmlHandle( 0 );
01661 }

TiXmlHandle TiXmlHandle::FirstChildElement (   )  const
 

Return a handle to the first child element.

Definition at line 1640 of file tinyxml.cpp.

References TiXmlNode::FirstChildElement(), node, and TiXmlHandle().

01641 {
01642         if ( node )
01643         {
01644                 TiXmlElement* child = node->FirstChildElement();
01645                 if ( child )
01646                         return TiXmlHandle( child );
01647         }
01648         return TiXmlHandle( 0 );
01649 }

TiXmlNode* TiXmlHandle::Node (   )  const [inline]
 

Deprecated:
use ToNode. Return the handle as a TiXmlNode. This may return null.

Definition at line 1674 of file tinyxml.h.

01674 { return ToNode(); }

TiXmlHandle TiXmlHandle::operator= (  const TiXmlHandle &  ref  )  [inline]
 

Definition at line 1620 of file tinyxml.h.

References node.

01620 { this->node = ref.node; return *this; }

TiXmlText* TiXmlHandle::Text (   )  const [inline]
 

Deprecated:
use ToText() Return the handle as a TiXmlText. This may return null.

Definition at line 1682 of file tinyxml.h.

01682 { return ToText(); }

TiXmlElement* TiXmlHandle::ToElement (   )  const [inline]
 

Return the handle as a TiXmlElement. This may return null.

Definition at line 1663 of file tinyxml.h.

01663 { return ( ( node && node->ToElement() ) ? node->ToElement() : 0 ); }

TiXmlNode* TiXmlHandle::ToNode (   )  const [inline]
 

Return the handle as a TiXmlNode. This may return null.

Definition at line 1660 of file tinyxml.h.

01660 { return node; }

TiXmlText* TiXmlHandle::ToText (   )  const [inline]
 

Return the handle as a TiXmlText. This may return null.

Definition at line 1666 of file tinyxml.h.

01666 { return ( ( node && node->ToText() ) ? node->ToText() : 0 ); }

TiXmlUnknown* TiXmlHandle::ToUnknown (   )  const [inline]
 

Return the handle as a TiXmlUnknown. This may return null.

Definition at line 1669 of file tinyxml.h.

01669 { return ( ( node && node->ToUnknown() ) ? node->ToUnknown() : 0 ); }

TiXmlUnknown* TiXmlHandle::Unknown (   )  const [inline]
 

Deprecated:
use ToUnknown() Return the handle as a TiXmlUnknown. This may return null.

Definition at line 1686 of file tinyxml.h.

01686 { return ToUnknown(); }

Member Data Documentation

TiXmlNode* TiXmlHandle::node [private]
 

Definition at line 1689 of file tinyxml.h.

Referenced by Child(), ChildElement(), FirstChild(), FirstChildElement(), operator=(), and TiXmlHandle().

The documentation for this class was generated from the following files:
Generated on Mon Feb 15 11:10:23 2010 for loon by  doxygen 1.3.9.1