Orocos Real-Time Toolkit  2.8.3
Public Member Functions | List of all members
RTT::marsh::TiXmlHandle Class Reference

A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. More...

#include <rtt/marsh/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
 Return a handle to the "index" child with the given name. More...
 
TiXmlHandle Child (int index) const
 Return a handle to the "index" child. More...
 
TiXmlHandle ChildElement (const char *value, int index) const
 Return a handle to the "index" child element with the given name. More...
 
TiXmlHandle ChildElement (int index) const
 Return a handle to the "index" child element. More...
 
TiXmlNodeNode () const
 Return the handle as a TiXmlNode. This may return null. More...
 
TiXmlElementElement () const
 Return the handle as a TiXmlElement. This may return null. More...
 
TiXmlTextText () const
 Return the handle as a TiXmlText. This may return null. More...
 
TiXmlUnknownUnknown () const
 Return the handle as a TiXmlUnknown. This may return null;. More...
 

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
}

Definition at line 1497 of file tinyxml.h.

Constructor & Destructor Documentation

RTT::marsh::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 1501 of file tinyxml.h.

RTT::marsh::TiXmlHandle::TiXmlHandle ( const TiXmlHandle ref)
inline

Copy constructor.

Definition at line 1503 of file tinyxml.h.

Member Function Documentation

TiXmlHandle RTT::marsh::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 1784 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChild(), and RTT::marsh::TiXmlNode::NextSibling().

TiXmlHandle RTT::marsh::TiXmlHandle::Child ( int  index) const

Return a handle to the "index" child.

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

Definition at line 1765 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChild(), and RTT::marsh::TiXmlNode::NextSibling().

TiXmlHandle RTT::marsh::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 1822 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChildElement(), and RTT::marsh::TiXmlNode::NextSiblingElement().

TiXmlHandle RTT::marsh::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 1803 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChildElement(), and RTT::marsh::TiXmlNode::NextSiblingElement().

TiXmlElement* RTT::marsh::TiXmlHandle::Element ( ) const
inline

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

Definition at line 1545 of file tinyxml.h.

TiXmlHandle RTT::marsh::TiXmlHandle::FirstChild ( ) const

Return a handle to the first child node.

Definition at line 1717 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChild().

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

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

Definition at line 1729 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChild().

TiXmlHandle RTT::marsh::TiXmlHandle::FirstChildElement ( ) const

Return a handle to the first child element.

Definition at line 1741 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChildElement().

Referenced by RTT::marsh::TinyDemarshaller::deserialize().

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

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

Definition at line 1753 of file tinyxml.cpp.

References RTT::marsh::TiXmlNode::FirstChildElement().

TiXmlNode* RTT::marsh::TiXmlHandle::Node ( ) const
inline

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

Definition at line 1543 of file tinyxml.h.

Referenced by RTT::marsh::TinyDemarshaller::deserialize().

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

Definition at line 1504 of file tinyxml.h.

TiXmlText* RTT::marsh::TiXmlHandle::Text ( ) const
inline

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

Definition at line 1547 of file tinyxml.h.

TiXmlUnknown* RTT::marsh::TiXmlHandle::Unknown ( ) const
inline

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

Definition at line 1549 of file tinyxml.h.


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