TiXmlHandle Class Reference

#include <tinyxml.h>

Collaboration diagram for TiXmlHandle:

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
• TiXmlNode * Node () const

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

• TiXmlElement * Element () const

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

• TiXmlText * Text () const

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

• TiXmlUnknown * Unknown () const

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

Private Attributes

• TiXmlNode * node

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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 ).Element();
	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 ).Element();
		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" ).Element();

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

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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.

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

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TiXmlHandle::TiXmlHandle

(

const TiXmlHandle &

ref

)

[inline]

Copy constructor.

References node.

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Member Function Documentation

TiXmlHandle TiXmlHandle::operator=

(

const TiXmlHandle &

ref

)

[inline]

References node.

TiXmlHandle TiXmlHandle::FirstChild

(

)

const

Return a handle to the first child node.

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

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TiXmlHandle TiXmlHandle::FirstChild

(

const char *

value

)

const

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

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

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TiXmlHandle TiXmlHandle::FirstChildElement

(

)

const

Return a handle to the first child element.

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

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TiXmlHandle TiXmlHandle::FirstChildElement

(

const char *

value

)

const

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

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

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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.

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

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TiXmlHandle TiXmlHandle::Child

(

int

index

)

const

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

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

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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.

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

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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.

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

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TiXmlNode* TiXmlHandle::Node

(

)

const [inline]

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

References node.

TiXmlElement* TiXmlHandle::Element

(

)

const [inline]

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

References node, and TiXmlNode::ToElement().

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TiXmlText* TiXmlHandle::Text

(

)

const [inline]

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

References node, and TiXmlNode::ToText().

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TiXmlUnknown* TiXmlHandle::Unknown

(

)

const [inline]

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

References node, and TiXmlNode::ToUnknown().

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Member Data Documentation

TiXmlNode* TiXmlHandle::node [private]

Referenced by Child(), ChildElement(), Element(), FirstChild(), FirstChildElement(), Node(), operator=(), Text(), TiXmlHandle(), and Unknown().

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

• tinyxml.h
• tinyxml.cpp