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TiXmlHandle Class Reference

#include <tinyxml.h>

Public Member Functions

 TiXmlHandle (TiXmlNode *_node)
 Create a handle from any node (at any depth of the tree.) This can be a null pointer. More...
 
 TiXmlHandle (const TiXmlHandle &ref)
 Copy constructor. More...
 
TiXmlHandle operator= (const TiXmlHandle &ref)
 
TiXmlHandle FirstChild () const
 Return a handle to the first child node. More...
 
TiXmlHandle FirstChild (const char *value) const
 Return a handle to the first child node with the given name. More...
 
TiXmlHandle FirstChildElement () const
 Return a handle to the first child element. More...
 
TiXmlHandle FirstChildElement (const char *value) const
 Return a handle to the first child element with the given name. More...
 
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
 
TiXmlNodeToNode () const
 
TiXmlElementToElement () const
 
TiXmlTextToText () const
 
TiXmlUnknownToUnknown () const
 
TiXmlNodeNode () const
 
TiXmlElementElement () const
 
TiXmlTextText () const
 
TiXmlUnknownUnknown () const
 

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 1647 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 1651 of file tinyxml.h.

TiXmlHandle::TiXmlHandle ( const TiXmlHandle ref)
inline

Copy constructor.

Definition at line 1653 of file tinyxml.h.

Member Function Documentation

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 1708 of file tinyxml.cpp.

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 1689 of file tinyxml.cpp.

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 1746 of file tinyxml.cpp.

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 1727 of file tinyxml.cpp.

TiXmlElement* TiXmlHandle::Element ( ) const
inline
Deprecated:
use ToElement. Return the handle as a TiXmlElement. This may return null.

Definition at line 1712 of file tinyxml.h.

TiXmlHandle TiXmlHandle::FirstChild ( ) const

Return a handle to the first child node.

Definition at line 1641 of file tinyxml.cpp.

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

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

Definition at line 1653 of file tinyxml.cpp.

TiXmlHandle TiXmlHandle::FirstChildElement ( ) const

Return a handle to the first child element.

Definition at line 1665 of file tinyxml.cpp.

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

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

Definition at line 1677 of file tinyxml.cpp.

TiXmlNode* TiXmlHandle::Node ( ) const
inline
Deprecated:
use ToNode. Return the handle as a TiXmlNode. This may return null.

Definition at line 1708 of file tinyxml.h.

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

Definition at line 1654 of file tinyxml.h.

TiXmlText* TiXmlHandle::Text ( ) const
inline
Deprecated:
use ToText() Return the handle as a TiXmlText. This may return null.

Definition at line 1716 of file tinyxml.h.

TiXmlElement* TiXmlHandle::ToElement ( ) const
inline

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

Definition at line 1697 of file tinyxml.h.

TiXmlNode* TiXmlHandle::ToNode ( ) const
inline

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

Definition at line 1694 of file tinyxml.h.

TiXmlText* TiXmlHandle::ToText ( ) const
inline

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

Definition at line 1700 of file tinyxml.h.

TiXmlUnknown* TiXmlHandle::ToUnknown ( ) const
inline

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

Definition at line 1703 of file tinyxml.h.

TiXmlUnknown* TiXmlHandle::Unknown ( ) const
inline
Deprecated:
use ToUnknown() Return the handle as a TiXmlUnknown. This may return null.

Definition at line 1720 of file tinyxml.h.


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