TinyXML-2
7.0.0
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#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. | |
XMLHandle & | operator= (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. | |
XMLNode * | ToNode () |
Safe cast to XMLNode. This can return null. | |
XMLElement * | ToElement () |
Safe cast to XMLElement. This can return null. | |
XMLText * | ToText () |
Safe cast to XMLText. This can return null. | |
XMLUnknown * | ToUnknown () |
Safe cast to XMLUnknown. This can return null. | |
XMLDeclaration * | ToDeclaration () |
Safe cast to XMLDeclaration. This can return null. | |
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.