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Public Member Functions

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 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.
TiXmlElementElement () const
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.
TiXmlNodeNode () const
TiXmlHandle operator= (const TiXmlHandle &ref)
TiXmlTextText () const
TiXmlElementToElement () const
 Return the handle as a TiXmlElement.
TiXmlNodeToNode () const
 Return the handle as a TiXmlNode.
TiXmlTextToText () const
 Return the handle as a TiXmlText.
TiXmlUnknownToUnknown () const
 Return the handle as a TiXmlUnknown.
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 1631 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 1635 of file tinyxml.h.

Referenced by Child(), ChildElement(), FirstChild(), and FirstChildElement().

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

Copy constructor.

Definition at line 1637 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 1674 of file tinyxml.cpp.

References TiXmlNode::NextSibling(), and TiXmlHandle().

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 1655 of file tinyxml.cpp.

References TiXmlNode::NextSibling(), and TiXmlHandle().

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 1712 of file tinyxml.cpp.

References TiXmlNode::NextSiblingElement(), and TiXmlHandle().

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 1693 of file tinyxml.cpp.

References TiXmlNode::NextSiblingElement(), and TiXmlHandle().

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

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

Definition at line 1696 of file tinyxml.h.

References ToElement().

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

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

Definition at line 1619 of file tinyxml.cpp.

References TiXmlHandle().

TiXmlHandle TiXmlHandle::FirstChild ( ) const

Return a handle to the first child node.

Definition at line 1607 of file tinyxml.cpp.

References TiXmlHandle().

TiXmlHandle TiXmlHandle::FirstChildElement ( ) const

Return a handle to the first child element.

Definition at line 1631 of file tinyxml.cpp.

References TiXmlHandle().

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

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

Definition at line 1643 of file tinyxml.cpp.

References TiXmlHandle().

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

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

Definition at line 1692 of file tinyxml.h.

References ToNode().

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

This may return null.

Definition at line 1700 of file tinyxml.h.

References ToText().

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

Return the handle as a TiXmlElement.

This may return null.

Definition at line 1681 of file tinyxml.h.

Referenced by Element().

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

Return the handle as a TiXmlNode.

This may return null.

Definition at line 1678 of file tinyxml.h.

Referenced by Node().

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

Return the handle as a TiXmlText.

This may return null.

Definition at line 1684 of file tinyxml.h.

Referenced by Text().

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

Return the handle as a TiXmlUnknown.

This may return null.

Definition at line 1687 of file tinyxml.h.

Referenced by Unknown().

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

This may return null.

Definition at line 1704 of file tinyxml.h.

References ToUnknown().


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