TinyXML-2  5.0.1
Public Member Functions | List of all members
tinyxml2::XMLHandle Class Reference

#include <tinyxml2.h>

Public Member Functions

 XMLHandle (XMLNode *node)
 Create a handle from any node (at any depth of the tree.) This can be a null pointer.
 
 XMLHandle (XMLNode &node)
 Create a handle from a node.
 
 XMLHandle (const XMLHandle &ref)
 Copy constructor.
 
XMLHandleoperator= (const XMLHandle &ref)
 Assignment.
 
XMLHandle FirstChild ()
 Get the first child of this handle.
 
XMLHandle FirstChildElement (const char *name=0)
 Get the first child element of this handle.
 
XMLHandle LastChild ()
 Get the last child of this handle.
 
XMLHandle LastChildElement (const char *name=0)
 Get the last child element of this handle.
 
XMLHandle PreviousSibling ()
 Get the previous sibling of this handle.
 
XMLHandle PreviousSiblingElement (const char *name=0)
 Get the previous sibling element of this handle.
 
XMLHandle NextSibling ()
 Get the next sibling of this handle.
 
XMLHandle NextSiblingElement (const char *name=0)
 Get the next sibling element of this handle.
 
XMLNodeToNode ()
 Safe cast to XMLNode. This can return null.
 
XMLElementToElement ()
 Safe cast to XMLElement. This can return null.
 
XMLTextToText ()
 Safe cast to XMLText. This can return null.
 
XMLUnknownToUnknown ()
 Safe cast to XMLUnknown. This can return null.
 
XMLDeclarationToDeclaration ()
 Safe cast to XMLDeclaration. This can return null.
 

Detailed Description

A XMLHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. Note that XMLHandle is not part of the TinyXML-2 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:

XMLElement* root = document.FirstChildElement( "Document" );
if ( root )
{
    XMLElement* element = root->FirstChildElement( "Element" );
    if ( element )
    {
        XMLElement* child = element->FirstChildElement( "Child" );
        if ( child )
        {
            XMLElement* child2 = child->NextSiblingElement( "Child" );
            if ( child2 )
            {
                // Finally do something useful.

And that doesn't even cover "else" cases. XMLHandle addresses the verbosity of such code. A XMLHandle checks for null pointers so it is perfectly safe and correct to use:

XMLHandle docHandle( &document );
XMLElement* child2 = docHandle.FirstChildElement( "Document" ).FirstChildElement( "Element" ).FirstChildElement().NextSiblingElement();
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.

XMLHandle handleCopy = handle;

See also XMLConstHandle, which is the same as XMLHandle, but operates on const objects.


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