eXperiment robotics framework

TiXmlHandle Class Reference

A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. More...

#include <tinyxml.h>

Collaboration diagram for TiXmlHandle:

Collaboration graph
[legend]

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
 Return a handle to the "index" child with the given name.
TiXmlHandle Child (int index) const
 Return a handle to the "index" child.
TiXmlHandle ChildElement (const char *value, int index) const
 Return a handle to the "index" child element with the given name.
TiXmlHandle ChildElement (int index) const
 Return a handle to the "index" child element.
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
TiXmlNodeToNode () const
 Return the handle as a TiXmlNode.
TiXmlElementToElement () const
 Return the handle as a TiXmlElement.
TiXmlTextToText () const
 Return the handle as a TiXmlText.
TiXmlUnknownToUnknown () const
 Return the handle as a TiXmlUnknown.
TiXmlNodeNode () const
TiXmlElementElement () const
TiXmlTextText () const
TiXmlUnknownUnknown () const

Private Attributes

TiXmlNodenode


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 1638 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 1642 of file tinyxml.h.

References node.

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

Copy constructor.

Definition at line 1644 of file tinyxml.h.

References node.


Member Function Documentation

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

Definition at line 1645 of file tinyxml.h.

References node.

TiXmlHandle TiXmlHandle::FirstChild (  )  const

Return a handle to the first child node.

Referenced by FirstChild().

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

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

TiXmlHandle TiXmlHandle::FirstChildElement (  )  const

Return a handle to the first child element.

Referenced by FirstChildElement().

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

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

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.

Referenced by Child().

TiXmlHandle TiXmlHandle::Child ( int  index  )  const

Return a handle to the "index" child.

The first child is 0, the second 1, etc.

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.

Referenced by ChildElement().

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.

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

Definition at line 1676 of file tinyxml.h.

References FirstChild().

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

Definition at line 1677 of file tinyxml.h.

References FirstChildElement().

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

Definition at line 1679 of file tinyxml.h.

References Child().

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

Definition at line 1680 of file tinyxml.h.

References ChildElement().

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

Return the handle as a TiXmlNode.

This may return null.

Definition at line 1685 of file tinyxml.h.

References node.

Referenced by Node().

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

Return the handle as a TiXmlElement.

This may return null.

Definition at line 1688 of file tinyxml.h.

References node, and TiXmlNode::ToElement().

Referenced by Element().

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

Return the handle as a TiXmlText.

This may return null.

Definition at line 1691 of file tinyxml.h.

References node, and TiXmlNode::ToText().

Referenced by Text().

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

Return the handle as a TiXmlUnknown.

This may return null.

Definition at line 1694 of file tinyxml.h.

References node, and TiXmlNode::ToUnknown().

Referenced by Unknown().

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

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

Definition at line 1699 of file tinyxml.h.

References ToNode().

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

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

Definition at line 1703 of file tinyxml.h.

References ToElement().

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

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

Definition at line 1707 of file tinyxml.h.

References ToText().

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

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

Definition at line 1711 of file tinyxml.h.

References ToUnknown().


Member Data Documentation

Definition at line 1714 of file tinyxml.h.

Referenced by operator=(), TiXmlHandle(), ToElement(), ToNode(), ToText(), and ToUnknown().


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

The miarn project - written by Joao Xavier