- Cal3D 0.11 API Reference -

cal3d::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>

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 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
TiXmlNodeNode () const
 Return the handle as a TiXmlNode. This may return null.
TiXmlElementElement () const
 Return the handle as a TiXmlElement. This may return null.
TiXmlTextText () const
 Return the handle as a TiXmlText. This may return null.


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
	    }
	    


Member Function Documentation

TiXmlHandle cal3d::TiXmlHandle::Child int  index  )  const
 

Return a handle to the "index" child.

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

TiXmlHandle cal3d::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.

TiXmlHandle cal3d::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 cal3d::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.


The documentation for this class was generated from the following files:
Generated at Thu Jun 29 19:04:00 2006 by The Cal3D Team with Doxygen 1.4.6